The short answer is you can't.
In the Gedcom standard the Residence fact, or for that matter other facts, are subordinate; that is not shared. Spouse and children are aggregated through a Family relationship and that's how marriage information becomes shared.
As you are aware media objects can be shared and so can Sources, but the citation detail cannot be shared so there's no shared Source/Citation.
In the standard there is a construct called a shared Note unfortunately not implemented for Ancestry Member Trees and not sure if it is implemented by FTM 2012. A common practice is to create a shared Note for a nuclear family as seen in a census and attach the Note to the various individuals.