Bc2000 (for the BCF2000 & BCR2000)

Hi all, I'm using Cubase SX3 and one BCF in Mackie mode, I would like
to make use of the 3 mixers in Cubase, for example set one up for
Drums, one for Guitars and bass and the 3rd for VSTs.

Is it possible to call up each mixer and when active use the BCF for
that mixer alone, mixer one is ok but when I use mixer 2 the BCF only
controls the last couple of channels.

Any ideas?

Thanks 

Colin