In my case Node A and Node B are very high capacity servers. On these nodes we are running our most critical instance(instance1). Currently the instance1 is running on Node A. Other two instances are for reporting purposes, so we are planning to run these 2 instances(intance2 and instance3) on node B. If node A fails for some reason, it should failover to Node B. In that case all three instances will be running on Node B. If needed we can manually failover the other two reporting instances running on node B to node C and node D respectively if we have any resource allocation issue.