Why not just put the synths you want to be driven by SEQ1 all on the same channel as SEQ1? Unless you mean you want SEQ1 to run two completely different sequences? If so, you may want to look at a polyphonic multitrack sequencer like a Pyramid. Three times the price, but it's polyphonic and has more than 3 times the track count. I use both. Beatstep Pro is so a great little sequencer.