To redirect rockets from the rocket launcher you can try 2 things.

One (requires 2 people)

Have one person get a rocket launcher and the other person get a gravity hammer.

et the person with the rockets to shoot a rocket at you (make sure that you are a good distance apart from each other so the rocket doesn't accidentally kill you).

When the rocket gets close enough hit it with the gravity hammer. The rocket should then spin of and not hit you.

Two (requires only 1 person)

Get a rocket launcher & sticky grenades.

Throw a sticky grenade ahead of you and then shoot a rocket over top of it (aim so that the rocket should fly over top the grenade).

If done correctly the rocket should be redirected into the air from the grenade explosion.