Here is a vRO action that I use to grab that sort of information. Hope this is helpful in some way.
var service = host.createCatalogClient().getCatalogConsumerResourceService();
var xObj = [];
var userArr = JSON.parse(userList.toLowerCase());
if (userArr instanceof Array != true) {
throw "Expected an array to be parsed. Check input string: " + userList;
}
for each (var user in userArr) {
xObj.push({"userid" : user,"username" : "","machines" : []});
var userIndex = userArr.indexOf(user);
var filter = new Array();
filter[0] = vCACCAFEFilterParam.substringOf("owners/ref", vCACCAFEFilterParam.string(user));
var query = vCACCAFEOdataQuery.query().addFilter(filter);
var items = service.getResourcesList(new vCACCAFEPageOdataRequest(query));
for each (var item in items) {
// System.log("Item: " + item.name + " owned by: " + user);
xObj[userIndex].machines.push(item.name);
}
}
var objOut = JSON.stringify(xObj);
System.log("Return value stringified: ");
System.log(objOut);