Last week I found out (by accident) that GarageBand 3 supports Rewire. It only acts as Master, though. Sounds from Live get nicely routed into GarageBand (or so it seems).
However, I usually rewire Reason into Live as well, but this doesn't seem to work anymore when I am using Live as a slave for GB3. Is there a way to make Live act as both a master and slave?