Try and look fornan output dun sa drum module. Most ofnthe time theresb2. 1 for headphones and 1 for pa. Tpos yung sa PA output stereo yun, pwede mo ikabit yung gamit yung regular instrumrent cable papunta sa aux in ng mixer mo, assuming na same sila ng input, kasi minsan yung aux ng mixer e nka trs. Or hanap ka lang ng inputnsa mixer mo and it should work.
Nice set up btw.