It is easy to bridge the amps into mono. If you download the current owner's manual there are diagrams on how to do it.  

In a nutshell it is just as simple as getting a Y-Cable (2 male, 1 female) for each amplifier's input jacks and a 12 inch piece of wire for each amp to connect the left positive speaker jack to the right negative speaker jack. The remaining unused positive and negative speaker jacks will be used to connect your speaker.