Here's my take on this...
Betty is picking on Veronica because she CAN! You are allowing it, and Veronica is allowing it, also.
Veronica is laughing because she is uncomfortable with the situation, and doesn't know what else to do... she has probably been told to not cause trouble, but she doesn't know how to stand up for herself. Don't you ever laugh in a situation because you are uncomfortable?
As the adult, you have the power and right to say that that kind of behavior WILL NOT be tolerated. If you see her bullying others, make her sit out. EVERY time....... Keep an eagle eye on that little bully! If she waits until the game or practice is over, but it is before they leave, then make her sit out the NEXT game as a consequence.
Some people, like Betty, pick on other people because it makes them feel better. Unfortunately, if you don't stop it now, it will be much worse, and Veronica and the others will feel that no one is going to speak up for them.
By standing up for the other girls now, you will empower them to be able to stand up for themselves.
You need to have a meeting with all of the girls, and tell them you see inappropriate "play", and that you will not allow it. Tell them that anyone caught behaving that way, will have to sit out the game, and possibly the next game, depending on when it happens.
Also, be sure to describe the kind of behavior you expect them to show at games and practices.