Bond of Sacred Unity

Choose up to four willing creatures in range. Those creatures now have one combined pool of hit points, and damage or healing to any of them accrues to that pool. If a spell of effect references a target's hit point maximum, each creature considers the maximum hit points in the pool as its maximum. As long as the pool has at least 1 hit point per subject of the spell, all of them remain conscious; however, if the pool drops below this at any point, the spell ends and all the recipients are reduced to 0 hit points.