If I remember correctly the LA Mod has a similar concept with Fire Station 1 where you can have either the Tower Ladder or Tiller in the same bay along with any of the ALS ambulances can park in the ambulance bay. Seems like all you would have to do is make the units you would call for a change of quarters a vo box for that bay. In my county in Rural Upstate NY upon the receipt of any Fire involving a structure (Building Fire, Chimney Fire, Smoke Investigation) the Home Department where the Fire is occurring has a Full Response of all Apparatus then you receive 2 Engine Companies, 2 Tankers, 1 Truck Company, and 1 ALS Ambulance from neighboring departments. Then for each subsequent alarm you receive an additional Engine Company, and Tanker.