Using the part combiner for hymns

[steveweb414]

Hi.  I'm working on a public-domain hymnal project.

I'd like to get the part combiner to follow some stemming conventions
that are common in hymnals:

- When the voices are in unison, there should be two stems.
- When the voices are a second apart (i.e. adjacent notes), there should
be two stems.

Is there a way I can get the part combiner to do this?

Thanks

Steve