Rights for an entire group

Hello!

When I create a zoomDoc, i can attibute a role for writing or not to the guests of my reunion. When I type the beguinnig of the name of a participant, i'm in a easy autocomplete process. But in that procedure, i sometimes see the name of my reunion among the participant's names. What does it mean? Can I attribute a role to the entire group instead of making that effort for every single member? 

Thanks
a.