Defensive Warm-Ups During Pitching Change?

 
With the bases loaded, the defensive coach visits his pitcher and decides to make a pitching change. During this mid-inning pitching change, the defensive coach tosses a practice ball to his first baseman and tells him to warm up the infielders by throwing ground-balls (similar to the infield warm-ups that occur between each half-inning). Is this permitted? Can bench players and/or coaches assist with the mid-inning warm-ups?
 
Call
There are prohibitions on the coaches warming up their defensive players during a pitching change. In addition, defensive teammates not already in the game cannot warm up their teammates during a pitching change. However, defensive players already in the game and on the field may warm-up with each other while the new pitcher takes his 8 warm-up pitches.