I am installing a 240/120 service entrance power panelboard (5 mains - out to 5 distribution panelboards), 400 A total. The NQOD interior was not supplied with a ground bar, so instead of adding a grounding buss with the EGC and then bonding it to neutral through the little bolt-on ground bonding pin, can I just add a few lugs to the neutral buss and connect EGC and outgoing ground wires. I will of course bond the frame/case of the panel to this bar as well. Does the NEC address this? Are there any safety issues to this proposal? Perhaps labeling/identifying the grounds versus neutrals is an issue?