Off-market commission for commercial property

Ladies and Gentlemen,

We are preparing to construct a new facility for our business- and move from our existing location to the new facility when it is complete. There has been a tremendous amount of interest in our existing property for many years- and we are often approached by brokers who indicate they have a potential buyer. Up until recently- we have never continued those conversations- as our property was never for sale. Now there is more interest than ever, and we are very confident that we can move the property off-market fairly quickly as we are in a very hot real-estate market. Of course we want to be fair to anyone who brings us a buyer- and pay them accordingly- but want to know what's fair for an off-market deal. Also- since the market is so hot (and properties like ours are extremely rare)- what are the chances that the buyer pays a portion of the commission? Also- if anyone has a resource for an agreement to cover such an arrangement, I'd love to see it. I've searched all over the Googlebot- and have not been able to find anything that is wholly appropriate.

Your comments and feedback are appreciated in advance.  We're in Florida- if that is important when replying.

JVN