> am looking for some help in connecting the common bus for 2 seperate systems

I believe you simply need an A-185-1 module in both systems, but I haven't actually tried this, so check with someone else first. As Rudy points out, though, this will only affect the oscillators and envelope generators, so you may not even need to hook up the two cases anyway. (For example, I have sound sources on my first row and envelope generators on my second, while the third row is just filters and effects, so I don't need to wire up the third row to the bus at all, even though it's in the same case.)

All the best,
Zoë.