Anyone ever set up masks to hide/enable cpu capabilities within vmware?

We have 4 hosts for our VDI setup, I'd like to get VMotion working
between all 4. Currently if you're trying to VMotion between the two
older ones to the two newer ones, it cannot be done w/o powering the VM
down due to CPU 'incompatibilities'. Certain portions of the cpu id
mask can be 'hidden' from the VM to allow for easier VMotion.

Any help on this would be greatly appreciated.