I think you are going to need a script to loop through the VMs.

create a Set Parameter Value step operation and then in the EVAL(javascript), recreate the variables there and make the HTTP calls.
You will need to output the call responses to a new ArrayList() table where the rows are set with a HashMap() of name value pairs.
There are lots of examples of how this is done with the cloud patterns like AWS.
And for the http calls, look at the custom operations page for RHV HTTP Get Call (see attached).