It would be an isolated G-bar,
see 250.146(D) 408.20EX in the 02', 384-20 in the 99' would also apply. Scott, has in past threads, expanded more than the average poster about the do's & don't of iso-installations.
I can't speak for listing standards, but i do note that there is no mention of MBJ or MDP as being the source iso-G in the NEC.
so comes the 'monkey wrench', am i in violation if i do not
run the iso-G back to these???