Hi Mario,
First you need to create a rule “Clustered services” and add all service which are clustered like your Diskgroups.
Then you create in Hosts a new object with "New Cluster " and add your cluster nodes to this object.
In the services you will see then the prior configured services. This services are OK as long as ONE Service on the nodes is OK.
Also, this services vanish from the host objects of the nodes. You will see a list of the clustered services in the WATO Service Discovery view at the bottom.
Hope that helps
Michael