Apply a range to Featureline Adjacent Elevation by Reference tool

[Neilw_05]

When using the Adjacent Elevations by Reference tool we don't have any control over the range of vertices that get modified on the target featureline. For example we may only want to adjust a portion of a featureline without affecting the adjacent portions. Without that control we have to resort to regrading the portions we didn't want to be affected. The process gets repeated every time we need to update the grading per changes in the reference featureline.

Can we have the ability to control the range that gets applied to the target? 

[doni49]

And since you're only changing a PORTION of the FL, we need a way to tell it what to do beyond that range.

i.e. you're changing between pt a & pt b.  But then from pt c to the end, I don't want it to change.  It needs to TRANSITION from the new pt b to the EXISTING pt c.