How map a Microsoft Distributed Transaction Coordinator (MSDTC) resource to an application that uses failover clusters such MSSQL Server, Exchange or MSMQ:
msdtc -tmMappingSet -name <MappingName> -service <SQLServerServiceName> -ClusterResourceName <MSDTCResourceName>

• To map MSSQLinstancename_1 to DTC resource in the same service or application group following command should be run:

Msdtc –tmMappingSet –name Mapping1 –service MSSQLinstancename_1 –ClusterResourceName MSDTCname_1

• To map MSSQLinstancename_2 to DTC resource in its own DTC service or application group following command should be run:

Msdtc –tmMappingSet –name Mapping2 –service MSSQLinstancename_2 –ClusterResourceName MSDTCname_2

• To check all mappings run the following:
  Msdtc –tmmappingview *