[HECnet] Disallow system from dz lines (OpenVMS/VAX 7.3)

OpenVMS VAX 7.3: This stops remote logins to SYSTEM even if correct password is provided (works for set host and telnet with Digital TCP/IP, though my version of MULTINET does not honor it). Is there a way to deny SYSTEM account access when correct password is provided from DZ lines? Network:? -----? No access? ------??????????? -----? No access? ------ Batch:??? ##### Full access ######??????????? ##### Full access ###### Local:??? ##### Full access ######??????????? ##### Full access ###### Dialup:?? -----? No access? ------??????????? -----? No access ------ Remote:?? -----? No access? ------??????????? -----? No access ------ Thank you. Supratim