Can Host Integration Server be installed on the same server as SQL Server?

We are just now investigating running the DRDA service to allow a mainframe to do some queries of SQL Server data. My reading so far indicates that we need Host Integration Server to have the DRDA service, but since this is the only use we would want to put this to, it would seem most efficient to run the DRDA service on the SQL server with communication taking place "internally" (i.e. to the "home" address 127.0.0.1) . Is this possible?