It would be similar to the current "branch" and "file path" scope limiting feature and would work based on the repository ID sent by the changeset.
With this feature, the same policy (and the same hook script package) could be re-used for many repositories (internal ticket id #4436).
It would also be nice to extend this a bit and increase this scope for a per-project scope-limiting rule, in the same way as what was done in v3.x of the plug in that now matches (or has rule policy) for a whole project.
Another suggestion - could you also add a "user in JIRA" condition as well since certain users can only be allowed to access certain repositories?
I know we can control user access to repositories separately from within BitBucket, but it would be easier if we have everything in one place (in the policy plugin). Just a suggestion. Thanks.