conditionally eliminating lyric extender

[Kieren MacMillan]

Hello all,

I want to [automagically] conditionally eliminate lyric extenders when
    (1) the end of the syllable which has the extender is after  
[i.e., to the right of] the melisma's last note; and,
    (2) the distance to the following syllable is less than the  
minimum extender length [plus some reasonable padding value?].

[Yes, I'm aware of Ross etc. and traditional rules of engraving — I  
also know that there are exceptions to every rule, and I think the  
one I'm suggesting is reasonable.]

For an example of the current default (v 2.13.3), I've attached a  
screenshot of my setting of Shakespeare's "Pardon, goddess of the  
night". It should be immediately obvious why I think the default is  
not optimal: in the case of "songs" and "Round", I would *definitely*  
want to eliminate the extender, and I might even want to eliminate it  
after "-bout".

My question is, what would be required to fix this?
Can it be done in the .scm files, or does it require a C++ modification?

Thanks,
Kieren.