Can I pursue criminal charges even if State Attorney's office didn't find enough evid

What is the name of your state? FL
My wife was assaulted by my ex-wife recently. My ex-wife slapped my pregnant wife in the face and then my wife grabbed her hair to prevent any further punches from landing. Somehow, an "independent witness" says that she haw my wife actually hit my ex-wife so the police sent the case to state attorney's office for review. I didn't see the hit, the only people that actually saw what really happened were my two daughters that I had with my ex-wife. They were upset that their mother hit their step mother. Also, a 16 year old girl that is friends with my ex-wife came up and hit my wife 3 times in the back with a closed fist and the police said that I couldn't prosecute her because, if you believe the independent witness, she was coming to the aid of my ex-wife. Confusing, I know, I just need to know if the state attorney comes back and says there isn't enough evidence, can I still push forward with criminal charges if I retain an attorney that can get aggressive?

No. The state is the one that pursues charges. All that YOUR WIFE can do is file a complaint. You don't have the standing to do either.

The district attorney, local prosecutor and/or your state attorney's office file criminal charges, not private attorneys. So if they review the case and don't find enough evidence to file charges against your wife or your ex-wife, then charges will not be filed.

You can have a private attorney file a civil case against your ex-wife for any damages she may have caused and recoup your medical expenses, but if there were no injuries to your current wife, then you will probably be spending more money on an attorney than you will recover from your ex-wife, even if she were found responsible for slapping your current wife. But with an independent witness taking your ex-wife's side, I doubt the ex would be found any more at fault than your current wife.

I would suggest that your current wife File a restraining order, or order of protection against your ex-wife so she doesn't have to worry about this type of confrontation happening again. If it does, then the police would have a legal reason to arrest your ex-wife.