How Do I Specify Trill Ending Notes??

I had occasion to need to enter a trill notation, along with the final notes for the trill that go in a different direction (down instead of the usual up of most of the duration for the trill). The closest I could come to entering it was to first use the "tr..." with waving line trill notation -- then, on the subsequent note or chord use two 32nd grace notes. However, that put the ending of the trill across the measure bar & into the wrong measure. Not only that, but the trill ending is not really grace notes in the true sense of the term! The ending notes of the trill should properly be at the tail end of the measure where the trill actually started. Isn't there a way to fix this -- using the equivalent of after-the-fact pseudo-grace notes that actually FOLLOW the note or cord, rather than preceding the next one? Thanks so much! Nolan W. Cook