It would be useful to have a test that created multiple parallel lines of communication over the cluster group of a reasonable amount of data, each using their own mptag, and check that the received data is correct (e.g. matches same crc/md5).
That will ensure test that there is no clashing and mp tagging separation is working properly.
NB: this is part to exercise different MP implementations e.g. MPI (See HPCC-8706)