Hi Brian,

Are there gaps between the notes? If there aren't, you may not need to do anything, due to this feature we added in 2014:

Legato Strings feature

For MIDI generated tracks (or MIDI SuperTracks), if the patch is a strings patch, instead of retriggering the same note, it will play a longer single note. This results in a smoother strings part, since only notes that are changing between chords will get triggered again. For example, if the strings are playing F and Bb for a Gm7 chord, and then a C7 chord comes and they play E and Bb. Now Band-in-a-Box will sustain the common Bb note since it doesn’t change, and only change the F to an E (assuming that the notes are intended to be played as sustained notes with no gap between them)

So as long as there are no gaps between notes, BIAB should be playing them as one sustained note automatically. Does it sound like this isn't happening?

Thanks
Kent
PG Music