Okay, I didn't want to put in the down arrows because it's kind of a Neolemmix-only feature that I wanted to avoid (I'm an old-school purist!!!) - still, in this case I think it's the only solution to patch the backroutes and kinda make the intended solution much more obvious. However, you can tell a digger to bash in this zone and it stops him - I consider this to be somewhat glitchy. Oh well, let's see what we get.