To make radio triggers:
1. Place a trigger
2. Activation: "Radio Alpha" (or wathever "Radio...")
3. Text: "text that wil be displayed next to radio #
To make the other squads attack:
1. First set all squads to "Hold Fire" & "Stealth"
(with a waypoint placed on top of the leader of that squad)
2. Next set the second waypoint on the town
"Open Fire" & "Seek & Destroy" & "Combat"
3. Sycronize the waypoint with your Radio trigger
Result (I hope) ;D : When you press 0-0-1 the squads head to the town and destroy all enemy units.
GRTZ
Vlaamse Leeuw