Oracle provides an association rules algorithm mostly aimed at the classical market basket case. Your project seems to expand the use of Association Rules into the search space. We have no methodology off hand to offer for this effort. Of course AR is built on top of frequent item sets, so to the extent you have an initial item then you could come up with a candidate list of consequent items with some probabilities. Perhaps that could be used to further broaden a search.
We could offer more assistance if you can get to the point where you have a defined methodology and have more specific questions on the use Association rules.