I believe the spell you are looking for is Fortunate Fate out of the Spell Compendium(latest version of the spell anyway).  It is Cleric 7 and can be cast on any living creature.  It lasts 10min/lvl or until discharged.  If the subject is killed in a way that a Heal spell can repair, a Heal spell is triggered on him/her/it and the target doesn't actually die(receiving the full effects of the Heal spell).  It is not the same as a contingent Heal and there are no apparent limits to the number that a creature can have active on them.  It would seem reasonable(to me, anyway) that if more than one are active they would all go off at once upon a single triggering instance.  That is after only a few minutes of thought about it though.  I hope that helps.