Is it OK for x32 and x64 clients to be in the same group?
--Yes, there is no issue with that
If we have both the 32 bit and 64 bit client in the same group for the auto upgrade you have to push the packge twice , once for 32 bit and next time for 64 bit
On the first time all 32 bit will update and 64 bit will reject the pacakge or we can say the install will fail
Second time vice versa will happen