Unity UI - Multiple Selection with Multiple Toggle Group

I am developing a game with Unity 2019 LTS. And there is a menu scene in the game. Player should select a character and difficulty level in that scene. Both of them have multiple options. For example, there are 2 characters and 3 difficulty levels(Easy, Medium, Hard). In order to accomplish this process I used Toggles and Toggle Groups like below.

Character Selection Toggle Group

• Character 1

• Character 2

Difficulty Level Toggle Group

• Easy

• Medium

• Hard

But, when player selects an option in one group, selected option in the other group becomes unselected. How can I solve this problem?