Well...
1) I need to make a map
This map would need to work with the escape concept. If you have an old map lying around that I could modify to test out my escape mode that would be good.
2) I need to figure out how to trigger it...Hammer doesn't really do well with variables and %s so this will be tricky.
3) Overview:
Basically the way the map would work would be the Terrorists start with no buyzone. However nearby there are a couple weapons caches nearby, just weapons lying in the floor or in boxes or something. So the Terrorists are kinda underpowered. However, they have a zone (or two) that they can enter. When they do they're teleported off the map. If 1/2 of the Terrorists get to the "escape" zone then all of the CTs get killed and every T gets a point. If the CTs kill 1/2 of the Terrorists then the Terrorists in the escaped area off the map get killed, the escape zone becomes inaccessible and the CTs all get a point. So that's basically how I'm gonna do it.