Need Expert in HL7 to answer questions

I've got several questions such as the following. ADT messaging is widely used in eHealth systems to exchange patient demographics information captured in one system (i.e patient admission system) to other systems (lab, radiology, etc). According to the following message, who is the receiving entity of the message and what is the patient's Master Patient Index (MPI) number? MSH|^~\&|Regional MPI||MPI|GRH|20160121140010||ADT^A28|3948375|P^T|2.4|||ER<cr> EVN|A28|20160101140008|||000338475^Author^Helen^^^^^ ^Regional MPI&2.16.840.1.113883.19.201&ISO^L| 20160101140008 <cr> PID|||000197245^^^NationalPN&2.16.840.1.113883.19.3&ISO^PN~4532^^ ^CarefulCareClinic&2.16.840.1.113883.19.2.400566&ISO^PI~3242346^^ ^GoodmanGP&2.16.840.1.113883.19.2.450998&ISO^PI||Patient^Particia^^^^^L||19750103|F|| |Pearson 23a&Randomroad&23a^^Newtown^^1200^^H|| 555 3542557^ORN^PH~555 3542558^ORN^FX|555 5557865^WPN^PH<cr> PV1||N|<cr>