All of the leader election tools like Consul, Zookeeper or any other quorum system. I've seen have been for pods within the same cluster. I need to coordinate across clusters for a tutorial.
The short answer for a broad question: It's not the norm but yes you can run them in different clusters as long as you expose your containers/pods with the right ports and IP addresses and they can find each other using these ports and IP addresses.
This answer relates to quorum systems that use a consensus algorithms like Paxos or Raft such as Consul, Zookeeper, Marathon, Chronos, Kubernetes, Mesos, etc.
Hope it helps!