Last month on Dream, my MIL was with us and my DW was booked in her room so she wouldn't have to pay the single supplement.
My wife got the OBB credit because she was the lead name on the reservation. It could not be split between the guests. (We just gave my MIL a Disney Gift Card to put on the room for the OBB credit.)
Since I was the one responsible for paying for my DW's charges, the paper printout of charges had me, DW, and my kids on the same print out. On the last night my MIL had asked me to get a copy of her charges while I was going to Guest Services to get mine; they would not give me a copy since they were not my charges (even though I had someone in the same cabin). So you and your friends will have private bills, as long as you each are only listed as being responsible for your own bills.
Only downside is that my MIL did not get our Disney Visa discount because the visa was not associated with her account.