A loose group of "hunting buddies" would not meet the criteria for a Part 90 business license. When you file for a license after obtaining the required frequency coordination you have to specify precisely how you will utilize radio in your business and when you submit it to the FCC you are certifiying the information is accurate and true.
Actually, Forest Industries Telecommunications, one of the main FCC part 90 frequency coordinators, advertises and sells a special licensing package gear toward hunters, motorcycle clubs, paintball groups, etc. For their $175 coordination fee, and $260 for FCC filing fees, they could get a statewide Itinerant frequency. Here is the PDF for the order form
http://www.landmobile.com/packages2009.pdf
Im not too sure which eligibility it falls under, maybe educational, but either way FIT advertises it.
Doing the whole Amateur license thing wouldnt be too bad either, but every time someone new wanted to join the hunting group, they would have to go through the testing process and wait for the callsign before being about to use a radio. They definitely would not want to use ham frequencies without a license, cuz hams will hunt down those doing it in a bad way, not something you would want to mess with!
At least with the Part 90 license, some joe blow could show up, and you just hand him a radio and he is good to go.
PM me if you want more detailed info.
Steven