You might use a report like the following example:
Select Top 1000000 tblADusers.Username,
tblADusers.Firstname,
tblADusers.Lastname,
tblADusers.Displayname
From tblADusers
Where tblADusers.Username Not Like 'admin%' And tblADusers.ADObjectID Not In
(Select tblADMembership.ChildAdObjectID
From tblADMembership Inner Join tblADGroups On tblADGroups.ADObjectID =
tblADMembership.ParentAdObjectID
Where tblADGroups.Name Like 'group1%')
Order By tblADusers.Username