Um… I have a suggestion for you.
Maybe you can also install Polis. There is an amazing feature in Polis.
/polis allowblock - Polis leaders can use this command then right click any block in their claim to toggle the blocks “right-clickability” by members of other teams.
However, you have to claim chunks in polis, and there is no message file.
Except Polis, I think GriefPrevention has the same function.The only problem is much more complex.