Bonded By Blood

You and up to three other willing creatures take 2d4 necrotic damage that bypasses resistance and immunity, and have your hitpoints reduced by that same amount for the duration of this spell. Then, each participant in the ritual has their maximum hitpoints increased by the total number of hitpoints reduced this way for the duration of the spell. In addition, all creatures under the effects of this spell receive half of the damage or healing received by any other creature from a source other than this spell. a creature can only benefit from this healing once per effect.