[Boost-users] Boost Graph Layout with Fixed Nodes

Hello, I wish to layout a graph using a force-directed layout algorithm, but where a few of the nodes are fixed. That is, there is a subset of nodes that have a predetermined position that must be maintained. Is it possible to achieve such behavior using one of the boost graph layout algorithms? I have been over the documentation for each and my conclusion would be that such behavior is not possible. Has anyone tried this before? Can anyone point me to some resources that aim to achieve this sort of layout? Any and all suggestions welcomed. Thanks. Regards, Donovan