Array of checkboxes to toggle on when another checkbox is checked

I'm creating a google sheet for Pathfinder characters (2nd ed). The skill system is represented by ranks and is displayed on the standard character sheet as a row of checkboxes. If a rank is checked then all the ranks below it should also be checked and the boxes above should become unchecked.

In the example below, since 'E' is checked then 'T' must also be checked. If the player were to then check 'L' then 'M' should also become checked. In the opposite case, if the player were to uncheck 'T' then 'E' should also become unchecked.

In effect, there are only five possible combinations.

One can give a formula for checkboxes and I've used this one for 'T'. And I understand how one could cascade such formulas. But the formula isn't going to work in this case.

=IF(I11,TRUE,FALSE)

I could use a drop-down to the right of the checkboxes and set their states based on that, but I don't like the way that looks. It breaks the translation from character sheet to the spreadsheet.

I want something like an event that I can use to set values based on user action.