I haven’t used OnSong for many years, I switched to SetList Maker/Bandhelper a long time ago and what you’re about is asking exactly what I do, or did do. If onsong has many of the same features as setlist maker/bandhelper then there should be a section to put in the PC for the preset and a CC for the Scene you want. I had these all programmed directly into bandhelper until a few weeks ago when decided to create a bunch of presets in the MMGT for all the songs I do and program the PC changes into the MMGT preset. All I do now in bandhelper is send the PC to the MMGT to choose that preset. I know I don’t need to actively have 512 accessible presets in the axe FX 3 and the MMGT has more than that anyway. So on the MMGT from preset 385 on up all the presets are song names and all the program changes and control changes for all my devices are built in. I would think you could at least do this with OnSong. However I should mention that I find it easier to just use the “IA Store” feature on the MMGT for things like scene selection or individual effects on the axe FX. I just pull up the preset on the MMGT it in turn pulls up the preset on the axe fx. If I want scene 2 for that song I select scene 2 then hit IA Store and it remembers to select that scene for that song. Sorry for rambling, just thought I’d offer a couple of options thinking at least one if not both could achieve what you’re wanting to do.. And by the way it’s a great idea. A little extra planning and programming at home means less headaches when you‘re at the gig.