Limit the number of nested list levels to 3

Hi everyone, we are looking into limiting the number of levels in the nested lists to 3 levels when creating a nested list in the editor and/or pasting a nested list from an external source. For example, when someone is pasting a nested list with 6 levels from Google Docs we would like to keep first 3 levels as is and convert levels 4-6 into flatten level 3. Would greatly appreciate any tips/advice on how this can be achieved. Thank you!

I think a transaction filter that prevents or modifies transactions that introduce too-deeply nested lists could do this. You’d also want to set up your interface so that commands that, say, add a new list level are disabled when you are already at level 3.

Thank you very much, Marijn! Really appreciate you taking the time and reply! Are there any documents or examples you are able to share by any chance? Thank you!