How do I split blocks that contain an imported midi file?

[christ0phe]

Hello,
I am importing midi files into LMMS. The midi is generated by MuseScore. It is a very simple score with only one instrument (a cello) that plays with arco or with pizz. I have two different instruments set up in LMMS. I would like to make parts of the imported midi associated to Instrument 1 and the other part (the complementary part) to Instrument 2.
The problem is that I cannot select part of the blocks that are populated with the midi import. The selection always take the entire score. Is it possible to somehow split the blocks so that individual ones are selectable the same way as if they were normal blocks without a 'coming-from-midi' content?
I hope my question is clear enough...
Thanks a lot in advance
Christophe

[diiz]

Select the notes you want in piano roll, copy, open a pattern on the other track in piano roll, paste?

[christ0phe]

Thanks for your proposal. Forgot to mention: the score is 200 blocks long and about 10 to 15 switch from arco to pizz so doing it in piano roll back and forth is a nightmare...