Add Segment-Based Metrics to Discover Conversion Funnel

If you look at the Discover conversion funnel below, it is typical for a Lead Gen site.  However, there is currently no way (that I know of) to add a new metric to this funnel that is based upon a segment.  Here is an example, let's say I want to treat "Visitors who view more than 3 pages on website" as a microconversion metric and I don't have it as a SiteCatalyst Success Event.  I might want to add this to the funnel below.  I can create a segment in a different Discover report that shows me how many visitors match that criteria, but there is no way to insert this into the funnel below.  Having this capability would be handy...