Unusual setup, Can it be done???

[balemon]

1 Data server, 10 workstations, 1 wingate box, 1 ADSL connection, 1 Dialup connection.
All workstations to access data server, and wingate box. 5 workstations to access dialup connection if logged in as user "x". If logged in as user "y" access is through ADSL.

CHeers
Brett