Add Person Group To List

DKnight1 What will be the column/data type of "Manager group" column?

As manager group is based on Category selected, I will suggest you to create a "Manager group" column in Category list.

Then, in lookup settings of Category column, you can extend the lookup column to show "Manager group" as an additional column.

Example: I am showing "SubParent" column along with "Title" column: 

Note: Lookups only support below column types:

1. Single line of text

2. Number

3. Date and Time

4. Lookup (single value)

Documentation: Create list relationships by using lookup columns 

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