Group to several people at the same time

[frankdarwin]

Is it possible to assign a group to several people at the same time?

[Mario]

No. Else it would be documented in the help. If its not in the help, it is not implemented.

All your questions related to person groups makes me think you are trying to abuse this simple feature.
It's just an optional and quick way to group people. One level. One group per person.
This is not designed to replace a category- or keyword-based organization of persons.

Do what other users do: Use IMatch categories or keywords to organize persons into multiple "Family" or "Group" categories/keywords. You have hierarchies, you can batch assign any number of people to any number of categories/keywords. You have filters. Sort options. You can show all these categories and keywords in the File Window. You can color-code. You can ...