Select Members of Group 48

There are only 32 groups (2020-08-07 — version 10.5.1) This may be here for future expansion, or they decided to not implement the use of the extra 32 groups. Sort of “user memory”? Group defaults? Named groups?

Groups inspector in Logic Pro — Apple Support

You use the Groups inspector to define the behavior of each Mixer group. The Groups inspector appears in the Track inspector when one or more groups have been created, and it can be opened as a floating window as well. It contains the following settings: