Sorry, but I’m also a little confused also. What does not being in the US have anything to do with using miles?
So, first thing I think we need to get clear is you can not “combine” all the miles from all your family members accounts and pool them together to get everyone a flight. One award flight (can be one way) needs to come out of just one MP account at a time. Again, this has nothing to do about being in the US or not.
You can’t take 10K miles out of 5 different accounts to get one 50K ticket. Hope I’m explaining this correctly.
It would help if you explained how many miles each member has, when you trying to go, and one way or round trip. I’m going to assume economy saver award tickets is what you are looking at, correct?