Migrate VM's form current cluster to another cluster (Like HA)

Hi,

I have 2 cluster and a host in each cluster. So if any Host down  is there any possibilities to migrate VM's form current cluester to another cluster (Like HA).

I need to enable HA at cluster level. I know it will not applicaple for cluster. could you please suggest any other way to migrate the VM's from one cluster to other.

Thanks