>select....
>group by Clients.ClientName..
>UNION
>select....
>group by Clients.ClientName..
>order by 1

Tried that one, got a "Missing ) parenthesis" error, wich only disapears when i remove the order by clause

>
>OR
>
>select....
>UNION
>select....
>group by 1
>order by 1

With this one, i kept receiving "Syntax error" all the time.
The weird thing is that i have in other apps much more complicated UNIONS in views, wich also have the group by and order by in the end, and work perfectly! I think i'm going to double-check i'm getting the right data in those views, before i get killed by my client...