Your sons seem to be involved in a pretend play that's normal for boys their age. Many mothers have expressed the same concern as you. However, be assured that this phase will pass. One of the most important things you can do now is to make sure your sons know that hitting and pushing aren't allowed. Let them know their safety is paramount and you won't tolerate them hurting each other or their friends. Are you familiar with the Rescue Heroes™ line of toys? They're action figures that promote safety and teamwork while saving those in distress. They were developed in response to the many mothers who said they want their sons to have wholesome role models for their kids to imitate rather than characters who use aggression or violence. Check out the Rescue Heroes website link for more information about them and the full range of toys, videos and online games. I'm sure your sons will have lots of fun playing with them.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.