you can actually get the virus's own "da da daa" arp to open and close the inputs on another channel :) - if its synced to midi clock then it will be pretty spot on

you can route internal outputs to the inputs in the virus and do it that way = or u can just take a wire out the back and patch it :)

im not going to explain how u do it tho cos i would have to sit down and think about it and its too late ;)