Here is what I would do ....
1) give all nodes access to their neighbours on the same tessellation level
2) for the quad node you want to render, find the neighbours, then if the node is an internal node (next door to the parent nodes neighbour) then go into the
parent nodes neighbours until your node is not an internal node and if they are of the same level of subdivision then you should be fine (if they are rendering patches at the same level for example) however if they are of a lower level of subdivision like in your diagram then find the tessellation level of the neighbouring nodes.
Then make a hem surrounding each patch just like in tessellation shaders and match the outer tessellation so that they match seamlessly, its pretty easy to set with hard coded numbers, you should google for OpenGL tessellation shaders and Direct 3D hull and domain shaders.
Edited by ray_intellect, 22 March 2013 - 02:15 AM.