It is possible to export multiple Unity objects into one FBX or OBJ file?

I have a city block I've carefully set up in my Unity scene. I want to combine all the objects together either as a prefab or one object. I also want to add details that are easier to add in Blender. My understanding is that you cannot merge objects in Unity, and that prefabs are made when exporting a file from Blender (or a similar software), which then shows up in Unity as a prefab. I have found addons and methods to export objects as FBX files, but I don't want to export 50+ objects by hand and then import them by hand as well. Is there any way I can export the whole scene, or multiple selected objects, to one FBX or OBJ file? Or a different solution to export all the objects as one into Blender?