Hmmm... I don't know how you might do it in Haptek, but it is possible to make a MSAgent which is actually two figures.
You would have to go through and make specific animations for each one, like:
Rob_Wave
Roy_Wave
Rob_GuestureRight
Roy_GuestureRight
Then make a plugin which prepends the "NEW and IMPROVED" MSAgent commands which Hal 6.1 is likely to have. Like:
GetResponse = <MSAGENT Rob_Wave> & GetResponse
... so that it switched back and forth.