a bit...

You have a HRM from GNC which counts calories, H/R, % of your max... and you want to keep that. But your HRM from GNC is interfereing with your cycling computer. Correct?

Why not replace the computer with the wire kind. You can find cheap ones and they are all still quite good. Since you already have a HRM, your cycling computer only needs the basic information, Avg speed, max speed, riding time, trip time, trip odo. and total odo. your basic 6 function computer. I think you can find them for around $20.00.