We finally tried a prototype of this. Selected a tech map as part of a captured allied base, created custom aliens of various types (workers, marines, sergeants, officers, priests) and had them holding the station crew captive while planting scuttling charges. We went in and disarmed the bombs and rescued the crew. Also put in an allied alien who we rescued to come along with us. We didn't get the balance quite right but it was a fun exercise.