I love golfing, but I wonder about what a rule is in respects to hitting your ball.?

Par 4 or 5. Your ball is in the fairway. Another golfer in your group smacks their ball and it lands next to your ball. If either one of you try to hit your 2nd shot you will wind up hitting the other ball with your swing. Is there a rule that allows a ball to be marked and moved so that your not hitting your partners ball??