When creating clash sets A/B you can either do this by selecting models or categories. Sometimes it is necessary to create clash detection only for specific elements that are part of whole model or category. Advanced search gives us list of specific elements (it can be upgraded to search by couple properties) and this list can be used in clash detection (even after model update Advanced Saved Search will give us updated results).
Another idea is to use Saved View which also has information which elements are visible. We can use these elements in clash detection. The disadvantage of this solution is that after model update we have to verify saved views for new elements.