<p>I think asking “Would that be ok?” makes it feel non-obligatory. If they would rather split the bill, this gives them the option to say “That’s a very generous offer, but it’s ok, we don’t mind picking up our part of the tab.” Just as long as you don’t make it a huge production, and not in front of the girls. Maybe pull one of the other girl’s parents aside and ask quietly and politely?</p>