Python recursive tree, linked list thingy

[Wanderer]

I have a list of defective CCD pixels and I need to find clusters
where a cluster is a group of adjacent defective pixels. This seems to
me to be a classic linked list tree search.I take a pixel from the
defective list and check if an adjacent pixel is in the list. If it is
I add the pixel to the cluster and remove it from the defective list.
I then check an adjacent pixel of the new pixel and so on down the
branch until I don't find a defective pixel. The I move up to the
previous pixel and check the next adjacent pixel  and so on until I'm
back at the head I can't find any more defective adjacent pixels. How
do you handle this sort of thing in Python?