So my bandmates (my best friends) want to play a show during Christmas break, we are in high school, but my family and I are going on vacation and I can't skip the vacation. But the show they want to play will be the biggest we have ever played and will give us a lot of exposure so they really want to do it. We would open for a band that plays there once every month and I would love to make it but obviously I can't. So they decided (mostly my guitarist/singer) that it would be in our best intrest to just get the bassist from the other band we are opening for to play with them. He did say he would do it too. But I don't want them too play it because I won't be there and since we are a power trio 1/3 of the actual band would be missing. He also wouldn't know what to play on our original songs because neither of my bandmates know how to play my bass lines so there is that too. Am I just being selfish and greedy, or do I actually have a valid point? Also what should I say to my bandmates to let them agree with me? (btw my drummer is 50/50 on the matter.