Recording with Boeringher 32

Our church currently uses a Boeringher 32 channel board, When I use the usb 2.0 interface to record to Audacity it uses all 32 channels even though we only use 8 or 9 at the most. The one time we tested it was a huge file that filled most of the computer free space. I was wondering is there way to set it in audacity to only record the channels that you want it to record. Right now we record with a memory card that we transfer to audacity to make it a mp3.

You can set the number of channels in the device toolbar.
The channels count up from channel 1 (this is not configurable), so if you want to record channels 1,2 and 5, then you would have to record 5 channels (1,2,3,4 and 5) and deleted the empty channels after recording.