The Romans had Vigiles as firefighters and police in ancient Rome.

I like to create these units for Rome and possible for conquered cities.

1. Is it possible to have units recruited from other buildings than barracks, perhaps municipal building?

2. What do I have to change in order to convert existing units, such as Funditores, into Vigiles, not the graphics (I do not know how and do have the software to create pictures)?

Your advise is greatly appreciated.