we dont have the tda 50 here in ireland but here is what we do on the tda 15,30,100,200.it may be the same setup.

lets say were working on icg 290.
the vm/grp is always set to grp 200 by def.
we setup another vm/grp of 265.
set intercept on grp 290 to 265
on vm if you setup mailbok 265 then claas to grp 290 intercept to that mailbox
if you dont setup m/box 265 calls to 290 intercept to the main menu.

worth a look

hope this helps peter...