I think this is around the area you're looking for:

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750x_3560x/software/release/15.0_1_se/configuration/guide/swipv6.html#wp1114198

An IPv6 host maintains a default router list from  which it selects a router for traffic to offlink destinations. The  selected router for a destination is then cached in the destination  cache. NDP for IPv6 specifies that routers that are reachable or  probably reachable are preferred over routers whose reachability is  unknown or suspect. For reachable or probably reachable routers, NDP can  either select the same router every time or cycle through the router  list. By using DRP, you can configure an IPv6 host to prefer one router  over another, provided both are reachable or probably reachable.