[LAU] multitrack export midi type 0 (gramophone2) issue

Hello, I have written generative composition with a chomsky grammar parsed by and *old* program called gramophone2. Unfortunately, my tests composition have multitrack but gramophone2 generates midi type 0 files (1 merged track). So, all midi sequencers i tried does only import track #1 while there are 3 or 4 in the midi file with different speeds (i'm playing with yet another phasing music). It may be a grammophone2 bug, but before to dive into the code (if i find it) how could i convert the generated midi type 0 into a type 1 so that tracks speeds can be aligned ? With the hope the question is well asked and not out of topic. - Benoît