A/C taking my runway

[johnbla 31]

I had an instance of taxiing at an uncontrolled airport using Unicom to a runway but waiting at the threshold for another aircraft to take off. As soon as that aircraft took off, I started to back track down to the take off position (the airport had no taxiways). I then had another aircraft came up behind me, announce that he was taking my runway and travel through me to the takeoff position. As soon as I got to the take off position, my FO announced taking the runway. Very unrealistic. I had filed an IFR flight plan.

Anyone know if there is a way of preventing this?

Thanks

John