Yes, I'm sure it's manageable. Though I don't think you have to go so far as calling the game's main loop just to get it to work. I would guess that remaining "inside" a callasm command for more than one frame might de-sync the game and screw things up but when I did something similar to this a while ago, I did it by returning from the "ASM level" to the "script level" each frame. So yeah, it's totally possible but you're going to need knowledge of ASM and a good chunk of time in order to pull it off.
Also, does the callasm command really stop the music? I thought that the sound data was copied over via DMA so that it would continue playing, which explains why people often describe the game freezing as "the screen goes black but I can still hear the music." :\