Integrating mentions and user relationships modules

Hello.

I have successfully installed Mentions with jQuery textcomplete library, which is a pretty cool solution, but I'd like to show in the suggestion list only users who has a relationship with the current user. That relationship was stablished using User Relationships module. Looking at mentions.module it seems I would need to modify the query in the function mentions_autocomplete($string =''), but I'm not sure if it is the right way and how to do it.
Looking at User Relationships module it seems that to know if a user has a relationship with the current user I should verify in DB if that user requester_id or requestee_id is the current user and if the user relationship status is approved.
Have you ever implemented such integration? If not could you advise how to change that code in mentions.module to add that query for requester_id, requestee_id and relationship_status?

Thank you