Ah, well then this topic really just got more interesting to me. I'm playing with a MF setup that I will not be able to purchase TTL bits for.
My phrasing of your question would be : What if I used the ST-E3 as a wireless master but a dumb trigger (side port sync, no TTL), but used the group A/B/C to dial up and down 600 strobes from that central point. It would be along the same lines as your question, with the master being a 600 instead of the ST-E3.
-Joe