If in the course of making a substitution, either the player entering the game or the player leaving the game intentionally plays the puck with her stick, skates or hands or intentionally checks or makes any physical contact with an opposing player while the player respectively leaving or entering the game is actually on the ice, then the infraction of “too many players on the ice” shall be called."
It is only between the two players making the change. Technically you can have 15 skaters all on the ice and as long as no one makes a play on the puck or puck carrier, too many man has not happened.