Using a power amp/mixer as just a power amp for a mixing console?

I'm not sure if this is the right place for this, but I couldn't find a better one. I was hoping someone could clarify some questions I have about setting up a PA system for my home studio. I recently acquired a Peavey XM6 amplifier/mixer and we've been running it through an 80 watt behringer wedge. We have a set of yamaha PA speakers that are on their way this week. I was wondering, since my peavey only has 2 outputs, and not a lot of control over equalizing, can I use it as a power amplifier for a mixing board? If so can I use it to hook up all 3 speakers. The yamahas are 150 watts each, but the floor wedge is only 80. I can't seem to find anything online about how to do this, or whether it is even possible. If not, what other options should I look at?

 

Sure, you can use it, but it only has one power amp output channel, despite the two jacks. I'd avoid connecting more than two speakers to it, and I'd be sure they matched. To connect all three speakers you'll likely need another amp.

You could continue using it to power your one wedge, connecting the monitor output of another mixing board to either a hi-z channel input or tape in or power amp in.

 

As Bouldersound said, the peavy only has 1 output (with 2 parallel jacks) and it can withstand a total of 4 ohms impedance load.
This meens that you can plug a maximum of :
1 x 4 ohms speaker
2 x 8 ohms speakers
4 x 16 ohms speakers

If you plug more speakers than this to your amp, you risk of damaging it.