Hi Eric
If I understand this correctly, you could try to find a thin spacer ring/washer that fits over the screw thread which them limits the amount of thread proud of the spacer ring/washer. Of course the adapter would be pushed back by the thickness of the thin spacer ring/washer.
Here are some examples from Scope Stuff in the USA. There are several in their stock list - search on "Spacer".
http://www.scopestuff.com/ss_scts.htm
http://www.scopestuff.com/ss_ttsr.htm
Cheers
Dennis