Are role based domains possible?
What I want to do is based on user role i.e. to display a different value list, and when user selects from the value list, I want to populate 2 SAP Fields

Yes, this is possible. Please use the LocalValueHelp statement:

if Q[Role=xxxx]

  LocalValueHelp F[fieldname]  domain=dom1


  LocalValueHelp F[fieldname] domain=dom2