How to have project pull specific label from SCM?

[Karr, David]

For better or worse, our Perforce projects use labels for versioning,
instead of branches (or anything else).  If Continuum will work for me,
I'll need to create a handful of projects for the same application, for
different versions.  Each one will specify a different label to pull
from SCM.  I don't see a way to do this in Continuum.  I was able to get
this to work with CruiseControl, but I'd prefer to move to Continuum if
it will work.