How do I feed two multi-channel amps from only two sets of preouts?

[viking]

Hey all,
I found the best prices so far on BlueSeas products:

Here's a link to the relay:
http://www.manventureoutpost.com/pro...287610%29.html

Here's a link to the "add a battery"
http://www.manventureoutpost.com/pro...287650%29.html