Not sure if there's any 'built-in' support but I've found that you can use the vCACCAFERestClient class to call the properties service API directly to get the properties in a property group.
Script looks something like this...
// input params
var host; // vCACCAFE:VCACHost
var groupName; // name of property group
var client = host.createRestClient("com.vmware.csp.core.properties.service.api");
var response = client.get("propertygroups/" + groupName);
for each (var prop in response.getBodyAsJson()['properties']) {
// iterate over group properties
}