Each person gets a key card with a number on it. The number is the same on every card, except for the last 2 digits. They are 01, 02, 03, 04, 05 and so on, depending on how many keys you request for that room.
When you get the bill, each charge has the number of the card that charged it next to the entry, so you'll know what was charged on card XXXXXXX01,XXXXXXX02 etc. I have had the CMs break out the charges and then charge them to each individual's credit card, and I have had CMs who would not do that. I think that may be the luck of the draw.
In any event, since you will know which card charged which expense, you can have it all put on your credit card and then get the cash from the individuals to put toward your credit card payment.
That's how we do it when we go with a group, and it has always worked fine.