Hi there. It would help a lot if you formatted your question with sample data and desired resultset. You can read about proper posting techniques here:
http://weblogs.sqlteam.com/brettk/archive/2005/05/25/5276.aspx
Here, ill get you started:
declare @groups table (CompanyId int, GroupId int, GroupDesc varchar(100), MaxUsers int)
declare @users table (CompanyId int, UserId int, GroupId int)
insert into @groups
select 10, 1, 'Admins', 10 union
select 10, 2, 'President', 1 union
select 10, 3, 'Manager', 5
Nathan Skerl