So here's the story ... two of my former roommates are international students and don't have their license or a car. The third is US-born and has both, but isn't sure she can come. The first two definitely want to come, but without the third they don't have a way to get there.
Would it be a breach of etiquette to ask another guest I know is coming from the same city (about 2 hours from the ceremony) if they'd be able to give a ride to my former roommates? I'd love for them to be there but I won't have time to make the 4 hour round trip to pick them up and drop them off. I gave someone a carpool to a friend's wedding because of the same situation and I didn't find it weird at all but I'm not sure about asking someone else.