Runner Interference USSSA

Question
Hey Tom, been a while but have a new question for you. Just this past week I was in Orlando, FL for the USSSA FastPitch World Series and while I wasn't expecting the asssignment as I've only worked 2 assignments in a 3 man system and neither at the rabbit. While working the Championship game for the 10u in the Atlanta Braves Stadium everything went ok and my 2 partners helped me greatly with understanding what to do as the rabbit. This by the way was my 19th game in 6 days and was a little drained of games starting at 8am and rain storms coming causing delays and not getting off fields til 10 or 11:30pm....... As it usually happens one team won and we had to have the dreaded "IF" game only this time at a different field more exposed to the heat. I asked my partner should I move in with only a runner at 2nd and a play at 1st incase there is an overthrow or other issue at 1st where I would need to cover him. His answer was yes and that the home plate umpire would move to 3d. I beleve he misunderstood my question which casued the following........With a runner on 2nd and the SS playing very deep the batter hits a solid line drive to her. I began moving into the infield, the SS was at least 20 feet to my left and no where near the running lane while the runner was at least 6 feet to my right and never hesitated while running to 3rd. I noticed the ball going to the SS and hit her on the right foot without her fielding the ball. An Appeal was asked and I and my 2 parners discussed the situation. I realize that I was in the wrong position but I still was following the play. The Plate said that he didn't see the interference and it was my call but my other and more senior parner (this being my First time there) began saying that it didn't matter where the fielder was it was interference and after stating his reasons and rule the Plate agreede which made me call the runner at 3rd out and dissalow the score moving that runner back to 3rd. You can picture the fallout in that scene which carried the rest of the game especially when the eventually lost.    My question is that how can it be interference when there is at least 25 to 30 feet between the runner and the fielder when the runner didn't stop or slow down? If this is a case for interference then the same could be said for an outfielder since they aren't too many feet behind the infielders at this level of play. I accepted the responibility for my error and while the parents were ballistic the losing coach was very understanding while the other coach said I did a great job ( of course). There is nothing in the rule book that gives any idea of closeness between the runner and fielder. Can you give me some clarification so I don't make the same error again. The UIC Chris Kroon told me of a great site online for FastPitch 3 man system but I wasn't able to write it down so if you have one please let me know.  Once again, Thanks for your insight and help...Jim

Answer
First of all you have not described interference.  You have not described anything the runner did to impede F6 from playing the ball.  Simply being in front of or close to is not enough.  

From the sounds of it the runner just ran in front of F6, nothing wrong with that.  I think you guys may have got this one wrong.  I would love to hear the rule and reasons the other umpire thought it was interference.