Connecting 2 E mottors

Hello! I have CTC dual with MIghtyboard electronics and changed firmware to Marlin (attached to post). I would like to control both E motors simultaneously, as one motor. I tried to use mixing extruder module but it didn't work because of thermocouples as termistors and thermal protection of marlin. Do you have an idea where I need to add a code line to connect both stepper motors?

Ps. I can't attached Marlin file so here is a link to soft [reprapy.pl]