a user can be in two groups?
 

user1 is in groupA
I'd like for user1 to be part of groupB though.

Do you know of a way to change that?

Thanks
Slaz

either add them from the command line using the useradd command, man useradd for more options.
or you can edit your /etc/group file and add the user in the appropiate group that way.

my bad, that command is usermod , not useradd to modify an existing user.