I took one snail out of my betta tank because I saw an attack. That snail is happily housed with a bunch of neon tetras and gives his tentaclage free rein as he tromps around the tank.
I had to move another snail out of my angelfish tank as I saw that they had eaten most of one feeler. The only place I had to put her was in with the betta, so I did that with some trepidation. I think she learned to keep herself coiled up rather tightly when she was with the angels because she usually moves around with her long feelers tucked around her eyeballs. I haven't noted any further damage, though, and the betta seems uninterested i her for the most part.
So, unlikely that you can control the situation at all unless you remove the deliciously tempting tentacles from the betta's reach.