When Xray is retrieving a permalink from a silo / social media service such as Twitter, it should look for an original post link starting with a simplified version of the original post discovery algorithm to start with.
Simplified algorithm: if there is a URL at the end of the content (trimming trailing whitespace, and close paranthesis/bracket if any), and that URL is on the same site as the "website" field of the silo profile of the requested permalink, then return that URL as original-post-url in the return result. This is similar to what Bridgy does today for discovering an original post as a destination for sending Twitter backfeed responses.
Recent POSSE tweets that would work with this and should produce a result:
Note that this will not work for POSSE tweets that use a non-canonical (redirecting) short-domain for their original post link and this is ok for now. It is worth considering for a future iteration. Example that should (for now) return no result: