Actually his administration should create the rules of decorum for white house press conference(s) etc for the press. He should revoke all passes and in order to get it back each member of the press need to sign off on the rules stating the read them and understand them. That is how I would do it.
If the want to act like children, treat them like children
If the want to act like children, treat them like children.
Nothing keeps children in line better than a good smack. Same for reporters.