[Feature request] - Connect notes in metronome mark

Sometimes there's a metronome mark with more than one note, with or without a tie. For example, the following score:
https://musescore.com/user/11523441/scores/7010878
Now we can only add non-unified SMUFL characters such as lyric elision or other dashes. However, this doesn't come to playback, nor Musicxml export. I hope the metronome mark can be really semantic, and then we can use lots of features in the xml definition. Musicxml has multiple notes allowed in metronome mark, and there are even tie and tuplet features. I've included these in our braille music translation software by manually inputing these features from Michael Good's email, so Musescore can be the first software to support special metronome marks, such as:
1. quarter-tie-16th = 120.
2. Quarter+quarter = quarter+quarter+quarter = 60;
3. triplet half+quarter = half;

Haipeng