Rather than fill up game lists with prequels/sequels i'm using the 'Additional Apps' feature to add this as an option on the game details screen. This works great but there does seem to be one limitation, when loading one of the additional apps it sends the romname of the parent game to LEDBlinky, not the romname of the game i'm actually playing. I've checked this with the LEDBlinky troubleshooter which confirms it's the parent name being sent.
I appreciate this is probably working as intended as this would mostly be used for variants of a single game which would (or should) have identical controls and art, but it feels like they're should be a workaround for this and i'm conscious I may have missed a setting somewhere!