Pheren
Simplest way is to get an option to buy for a long term for any price before sending investor over to look and let him know you have an option, but he can negotiate his deal and you will release your option when you get the bird dogging fee.
That way the investor knows and the seller knows, and you won't have any trouble winning in small claims court if they try to circumvent you. Plus I hope you put those investors on your destroy them list, and screw them as often as you can, whenever you can, as often as you can. We don't need low life greedy investors adding to the public's image of us.