Define segments by idea attributes in addition to organization attributes

Currently, segments are defined via attributes on the organization. In our use case, this isn't useful because we need a segment to be based off more granular idea-level attributes.

For example, one way we'd like to use these is in preparation for a trade show. The trade show segment might consist of 7-8 organizations. However, the segment-level view isn't useful, because we still need to filter the relevant ideas down further based on idea attributes, to create the correct list of ideas that are relevant to the segment. We can accomplish this by filtering down individual reports, but it would be easier to apply those filters at the segment level- for example, a segment would consist of organizations who fit XYZ criteria BUT ONLY ideas that are associated with specific categories.