Coaching during league play

Question
A bowler coaches a bowler not on his team and not bowling against his team during league play.  Is there rule against this?  
It causes problems with the third party team.
I am the President of a bowling league and cannot find the answer at BOWL.COM (USBC website).

Answer
Ted,
You may be aware of a ban on coaching at the Professional Bowlers Association level. No coaching is allowed for the players on a PBA TV show. No other limitations exist for coaching bowlers during competition.

You would need to create a rule for your league. Unfortunately, once you begin the season, rules must be ratified by 100% of team captains for a rule to be changed or added (I believe).

As the President, you can talk with the coach, share that others are unhappy with his actions and ask him to coach before or after the league session. Suggest that it delays competition and that others are unhappy that it is happening. And that you don't want it to effect peoples enjoyment of the league sessions or for it to potentially effect bowlers willingness to continue to participate.  

Thanks for the question.