How do you handle employees complaining about one another?

Every once in a while I have team members who will complain about one another. The problem is that some of the things they complain about are not things that I have a major problem with. I usually tell them that I have to choose my battles but the complaining is just a weight on me. I don't want the team member that is complaining to feel like I don't care, or don't hear them but sometimes its just not a hill I want to die on. Hope that was enough information to answer this. Look forward to hearing how some of you handle team dynamics. Thanks in advance!