Synergy

Synergy is when two or more faces work together to produce a result not obtainable by any of the agents independently.
There is also media synergy which means different elements of a media congolerement work together to promote products across different media. Synergy works when different elements with media conglomarete products. AOL and Warner Brothers merged in 2000 in order to create the soudtrack for the megafranchise Harry Pottter.
The term synergy comes from Greek word syn-ergos, συνεργός, meaning 'working together'.