From version 4.1.0 of the Dynamic Categories Module, it is possible to build rules in progresseive steps of results. 

You can insert a new SUB RESULT combiner, which will use the result from the preceding rule sets to limit the results of the linked rule set.

Using SUB RESULTS, you can build a category by combining the results of multiple rule sets, progressively to one result. 

Sounds confusing? It is really very simple, and an example will explain it best. 

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