multi-package and flavors

Hi,
I'm making a port of devel/spyder that has the python3 FLAVOR.
now, spyder and spyder3 have the same docs, so even when the
applications files do not cause a conflict, the docs files do.
So I just divided the port in 2 packages -main and -docs, but the idea
is to create 3 at the end:
- spyder
- spyder3
- spyder-docs
So no collisions and 0 problems, my question is, how do I set the
multi-packages and the flavor without generating a 4th package.
Example attached and also in openbsd-wip on github under devel/spyder.
https://github.com/jasperla/openbsd-wip/blob/master/devel/spyder/Makefile

Thanks for the help.
Elias.