using two mboxes

I'm alone in the studio waiting for the others in the band - who are more technologically inclined than i am - to appear, and i'd like to set up our business to simultaneously run off of two Mbox imputs.

I'm running Protools LE 7.1.1 on a macbookpro, and i've got an Mbox and an Mbox 2 hooked up. By going to Setup -> Hardware, I can select either Mbox, but I cannot figure out how to (or if there is a way to) have Protools work off of both mboxes, simultaneously. Sometimes you just want a whole bunch of inputs, you know?

I've tried googling and searching around digidesign's website, as well as perhaps not-as-thorough-as-i-could-have-been searches of some forum, so if there's an obvious answer that i should have found on my own, my apologies.

Thanks.