I don't think its a mater of if one pilot group would like to fly the other, I personally don't give a rats where or what I fly, its more about the contract. (that I signed a long time ago and would like to keep)
I agree with what hkgfooey said, there is no advantage for cx to merge the lists, just an expensive pointless exercise.
If they wanted to move crews around they can do it on secondment, many other airlines do this, but even so, why rob Peter to pay Paul.
Both airlines are short on crew.