Call back and tell them there are only two (or four) of you. I've found that the agents on the telephone tend to try and enforce all sorts of absurd and seemingly made-up rules like this. The hotels couldn't be bothered with this kind of thing once you show up.

I have two small kids. I've had agents refuse to make reservations when I tell them there are four of us (for a European hotel that claims 3 max in a room) and then tell them "Okay well then there will be only two." After calling back I had a reservation with no problem. When we showed up, the hotel had no problem either.