Midi chords and coll

Hello!
I'm trying to make a simple midi synth where single notes played on a keyboard trigger chords consisting of multiple pitches, which are later sent to a synth within a poly~.

In the pasted patch below, there is some text in a comment box which is configured for coll to output 15 chords, based on midi notes/descending scale 72-57. You can create the text file for the coll to read by copying the text from the comment box.

But, of course, because the serial nature of midi, and because I don't know how to format each note to on/off and velocity messages, you only get the first note of each chord rather than all the notes.

Perhaps someone out there could point me in the right direction for 1) how to convert the list of chord notes into series of several midi pitches sent as a sequence, and 2) how to control the notes in a chord with the on/off and velocity info of the original trigger note?

Many thanks!
N