There are 2 floating chroma engines in Carbonite Black Plus.
Are you keying a single camera source on 5 different backgrounds? Or keying 5 individual camera sources?
If you are keying a single camera source, you can turn on layer mode on an ME, and use its Program and Clean Feed outputs as Video and Alpha sources on any keyer.
But if you are keying 5 different camera sources, then chromakeying 2 sources is the maximum.
#Carbonite