Are you just using the trial month of live for 4 accounts or are you paying for four live accounts? Lol
Prior to the Xbox One announcment Microsoft had something called the "Family Plan". For $99 a year your entire family (up to 4 acounts) could have gold accounts.
I've done that for 3 years now until Microsoft did away with the program at the Xbox One announcement. The gold runs out on all 4 accounts sometime in the middle of next year at which point I'll have to renew them separately.