Can this flange be doubled-up somehow?

This is part of a picture from a previous thread but not related to the carrier so I figured it is better to start a separate thread. This flange is the waste connection to a wallmount toilet but the builders did not make it stick far enough out. I cannot get any finish wall in there thin enough to make it extend the required 5/16" from that finished wall. Unfortunately it's not moving at all and isn't part of the carrier. Probably not even a screwed nipple but glued in. It looks like ABS.

Is there something like an additional ring that I could expoxy on? Or is there any other option?

Bob NH gave me hints how to salvage the carrier but without extending this flange I can't really do it unless I rip out all the wood and saw some custom pieces.

Regards, Joerg.

Today in HD, I saw a 1/2" extender kit. Looks like a thick white plastic shim with a gasket on one face. About 18 bucks.

.../j

Hello JCH,

Thanks! There is a HD about 10 miles from here so I'll check that out. 1/2" would just about hit the spot in this situation.

Regards, Joerg.