Synchronous Caster

If you and at least one allied creature are within 5 ft of each other and are able to cast the same spell you can use your action to synchronize your casting to empower the spell and cast that spell at a higher level. Your collective spell gains an additional level relative to the number of creatures casting the spell up to 9th level. You and any creature involved in the casting expend a spell slot of the original spell level. Allied creatures involved in the casting lose their action for the round. You may use this feature once per long rest.