6x6 mode : limiting the number of parts

It would be great to be able to limit a 6x6 song to a minor number of parts.
for example in the “edit song” menu I could choose “number of activated parts = 3”
It would make the 4th, 5th and 6th parts unavailable , so even if they were already recorded, I could not select them with the “next part” button.
If this is too difficult to implement : this option could be limited by the number of parts that are already recorded (if there is 4 parts already recorded, you can choose “number of activated parts = 4 or 5 or 6 but not 2 or 3”
If this is too difficult to implement, this option would be present only when creating a song : when creating a new 6x6 song, the user can choose the number of activated parts (6 by default)
The best option from the user point of view (but maybe the less realisable) would be to be able to select in the “song edit” menu which parts are activated or not (for exemple : activated parts : 1 yes, 2 yes, 3 no, 4 no, 5 yes, 6 no) (in this example, the next part button would cycle throught 1 → 2 → 5 → 1 …)

in 6x6 mode, I rarely use all the 6 parts. Let’s say that I created 3 parts and I want to cycle throught them (1 → 2 → 3 → 1 → 2 …)
I use the option “auto song part change (6x6)”.
Using the “next part” button I often accidentaly create a new part when I want to cycle from the last part (the third part) to the first one because I forget to tap twice this button (a first time to select the empty fourth part that I don’t need, and a second time to select the first part)
I can cancel the recording on the 4th part but it’s impossible to completly remove this unwanted part. So now I have to tap 3 times the next part button (first time to select the erased 4th part, second time to select the empty 5th part, and third time to finally select the 1st part)

Do you think that it’s possible to implement this ability to restrict the number of parts of a 6x6 song ? It would be so much easier to use the 6x6 mode !