Here's what I would do (I'm assuming you're not recording into a computer, right?):
Get yourself a used Mackie 1604VLZ. This console has 8 direct outs, and also 4 sub groups (with their own dedicated outputs).
You can keep your drums mic'ed up the way they are, plug your mics into any of the channels from 8-16 and then assign all your mics to one of the sub-groups, and send that output to the R16 - so you can even send all your drums mono and free up seven channels on the R16! The rest of the band can use the other channels on the Mackie (1-8), and you can either group some, or take a direct out to a corresponding channel on the R16. Voila - now you're mixing the entire band into the 8-tracks of your Zoom.
Pretty nifty, eh?