BA has the Household Account. All members earn their own miles that go into one account. Then anyone IN THAT ACCOUNT can use any of the miles. If you want to give a trip to someone that is not a member of the account then you have to disolve the account and one person must have enough miles to cover the free ticket. This is a good plan if you have one or two high earners and the others that are low earners can pool the miles with the high earners and use the miles. I just disolved our account to get a ticket for the step-son. Easy to do.

If you have more than four members then set up two Household accounts. Should work.
Hope this helps.