Russia and China may be relatively big players compared to North Korea, but they won't be able to provide much. North Korea is just too far out in left field for them to risk their necks over.
Kim is stalling for time. He would have preferred to let 2 way talks fail first, then let multi-party talks fail. This will cut months off of whatever deadline we intent to impose. We could be seeing a blockade or serious constrictive action against the DPRK within a few months.
You know, this could be where the human right angle could come handy. Even in the midst of this 6-way negotiations, America and China can still create refugee camps in China and take in N. Koreans. Since they are only helping hungry N. Koreans, N. Korea cannot accuse them of destabilization and hold it off.
Therefore, America could keep up the pressure by building the camps one building at a time.