How to search a certain variable in a list of a created class (C#)

Wasn't to sure how to word the question so here's a description with code below.

I have a list which takes type of Room (a class i created) and this class has a contructor to create many instances of itself with 2 parameters one being a enum called Size and another being a Vector3 called position. What i want to do is make sure when i create a new room its not being created on another at the same position, which i've done sucessfully with many switch statements which yes i know doens't look the prettiest but i'll clean it up later. However I need to check and see if the list "Contains" this position in the Room the problem is the List is of type Room and I need to check a part in it.

Since I cant do if(!rooms.Contains(room.position)) and can only do if(!rooms.Contains(room)) which i dont know if its checking that position variable and am getting a infinite loop, which is why the while loop is marked out. Sorry if the description is poor if you have any questions leave a comment. And here is the code

Room class

 public class Room {
 
     public Size roomSize;
     public Vector3 roomPos;
 
     public Room(Size zRoomSize, Vector3 zRoomPosition)
     {
         roomSize = zRoomSize;
         roomPos = zRoomPosition;
     }
 }

MapGenerator Class

-Part i'm having issues with

             Room newRoom = new Room (newSize, newPos);
 
 
             //What I want but can't do :(
             if(!rooms.Contains (newRoom.roomPos))
 
             //What i can do but doesn't work how i want because its checking the size also and I only want it to check the position 
             if(!rooms.Contains (new Room(newSize, newPos)))
             {
                 rooms.Insert (0, newRoom);
             }

-Whole code (Yes i'll clean it up later right now i just want it to work and i'm so close :) )

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class MapGenerator : MonoBehaviour
 {
     public List<Room> rooms = new List<Room>();
 
     public enum Size {small, medium, large};
 
     public int maxRooms;
     public GameObject smallRoom;
     public GameObject mediumRoom;
     public GameObject largeRoom;
 
     void Start()
     {
         rooms.Add (new Room(Size.small, Vector3.zero));
         GenerateMap ();
     }
         
     void GenerateMap()
     {
         //while(maxRooms > rooms.Count)
         //{
             SetNextRoom (rooms[0], 3);
         //}
         for(int i = 0; i < rooms.Count; i++)
         {
             GameObject roomObj = null;
             switch (rooms[i].roomSize)
             {
                 case Size.small:
                     roomObj = Instantiate (smallRoom, rooms[i].roomPos, Quaternion.identity) as GameObject;
                     break;
 
                 case Size.medium:
                     roomObj = Instantiate (mediumRoom, rooms[i].roomPos, Quaternion.identity) as GameObject;
                     break;
 
                 case Size.large:
                     roomObj = Instantiate (largeRoom, rooms[i].roomPos, Quaternion.identity) as GameObject;
                     break;
             }
             roomObj.name = "Room Number: " + i + " " + "RoomSize: " + rooms[i].roomSize + " RoomPosition: " +  rooms[i].roomPos.ToString ();
             roomObj.transform.SetParent (this.transform);
         }
     }
 
     void SetNextRoom(Room previousRoom ,int maxPaths)
     {
         for (int i = 0; i < maxPaths; i++)
         {
             int randomIntDirection = Random.Range (0, 4);
             int randomIntSize = Random.Range (0, 3);
 
             int offset = 0;
             Vector3 newPos = previousRoom.roomPos;
             Size newSize = Size.small;
             switch(randomIntSize)
             {
                 case 0:
                     if(previousRoom.roomSize == Size.large)
                     {
                         offset = 50;
                     }
                     else if(previousRoom.roomSize == Size.medium)
                     {
                         offset = 40;
                     }
                     else
                     {
                         offset = 30;
                     }
                     newSize = Size.small;
                     break;
 
                 case 1:
                     if (previousRoom.roomSize == Size.large)
                     {
                         offset = 60;
                     }
                     else if (previousRoom.roomSize == Size.medium)
                     {
                         offset = 50;
                     }
                     else
                     {
                         offset = 40;
                     }
                     newSize = Size.medium;
                     break;
 
                 case 2:
                     if (previousRoom.roomSize == Size.large)
                     {
                         offset = 70;
                     }
                     else if (previousRoom.roomSize == Size.medium)
                     {
                         offset = 60;
                     }
                     else
                     {
                         offset = 50;
                     }
                     newSize = Size.large;
                     break;
             }
 
             switch (randomIntDirection)
             {
                 case 0:
                     newPos.z += offset;
                     break;
 
                 case 1:
                     newPos.z += -offset;
                     break;
 
                 case 2:
                     newPos.x += offset;
                     break;
 
                 case 3:
                     newPos.x += -offset;
                     break;
             }
             Room newRoom = new Room (newSize, newPos);
 
 
             //What I want but can't do :(
             if(!rooms.Contains (newRoom.roomPos))
 
             //What i can do but doesn't work how i want because its checking the size also and I only want it to check the position 
             if(!rooms.Contains (new Room(newSize, newPos)))
             {
                 rooms.Insert (0, newRoom);
             }
         }
     }
 }