WoWInterface - Classic addon to check who is in raid group.

So basically what I'm looking for is an addon or weakaura that would allow me to input the names of the raiders on our roster and then, the addon would check who is in the raid group compared to the list of names. If we're missing players, the addon would let me know the names of the players not currently in raid. Sometimes when forming our raids we're short a few people and then we compare who is in the raid to who is on our roster but with 40 people it takes a few minutes so I'm just looking for an easier and faster way to know who's missing.