current business group

Hi,

Can you please help me to find query the business group that current (or specific user) is belong with VRO?

I was trying to do it on that way but getting null:

//vcacHost and userName are input parameter

var model = "ManagementModelEntities.svc";

var entitySetName = "Users";

var property = new Properties();

property.put("UserName",userName);

var entities = vCACEntityManager.readModelEntitiesByCustomFilter(vcacHost.id, model, entitySetName, property, null);

//System.log("User ent: " + entities);

var BG = entities[0].getLink(vcacHost, "ProvisioningGroup");

System.log("Bg New: " + BG);

Thanks,

Anat