If you have the channels though, and do not need your Group Busses for recording, you could also try some creative routing. For example:
1. Turn off your speakers.
2. Make sure your groups are not "directly assigned to the stereo buss" on the ASSIGN BUSS screen.
3. Patch the ADAT in into the ADAT out.
4. Route Groups 1-8 into the ADAT Out (I/O OUTPUT SELECT page.)
5. Route the ADAT in as an input source for channels 25-32.
6. Set faders to Unity and sends for Aux Send 1 on Ch 25, Aux Send 2 on 26, and so forth for all 6 aux sends. Make sure the channels are not assigned to stereo or groups.
7. Now you have 6 new Aux master faders with eq and compression. You can route 4 auxes out the assignable analog outs, and 2 as inputs to the internal effects. Or maybe out a TDIF out or something.(see the I/O OUTPUT SELECT page again.)
Also If you need a few time delayed feeds for a multiple speaker setup live, you could also patch ADAT out to ADAT in, make the stereo mix the input to the ADAT OUT 1-8, bring them back into faders and use the assignable delays on the channel delay page.
But always turn your speakers down before you do these things, in case you misroute and create a feedback loop!