[Boost-users] [BGL] truncating dijkstra_shortest_paths

Hi, in a given graph I want to determine whether between one (!) pair (u,v) of vertices there exists an u-v-path of length at most some given threshold and that path. I use dijkstra_shortest_paths(g,u, but to accelerate matters I would like to stop the computation as soon as the key of v becomes smaller than the threshold or v turns black. I couldn't find a hook of the dijkstra algorithm that could be used to achieve this. Do I really have to change the implementation of the dijkstra algorithm for this, or is there a better way? Thanks sven