OPL3/GM Hybrid soundfont?

Is it possible to make a soundfont that utilizes both the OPL3 and GM soundfonts? Been experimenting with my SF2s and made something with VirtualMidiSynth where OPL3 plays but the GM drums also play as an extra layer. What would be nice is if both were simultaneously loaded to have both sample packs play together. I really like some of the OPL3 sounds, but I don't want them to necessarily have to replace the GM equivalent.

You could try Viena or Vienna, both are soundfont editors. The former's free and named after the latter.

OPL3 isn't a sound font, so you'd just get an imitation of it. One could imagine a VST setup where you have one OPL emulator as a VSTi (here's one), and a normal GM soundfont as another.

Why not just sample the OPL3 instruments into their own SoundFont? Then add in any other non-OPL3 stuff you want. SoundFonts are nothing but sample packs with some extra playback info anyway.

The OPL chips already have a lot of subtleties going for them that are not emulated perfectly. Just sampling some arbitrarily chosen samples (produced by an arbitrarily chosen set of FM timbres) is not going to help much deliver an "authentic" OPL-like sound.

So, sample the Doom FM timbres? The Voyetra OPL3 timbres under Windows 3.1? The miserable "squarewave banjo" FM timbres used by default under Windows XP?

Reasons I sometimes miss Win98: you could set the MIDI mapper to play different channels on different devices.