Build a Website

I just acquired a small real estate company in Costa Rica and I need to build a website. It will most be a typical real estate site with pages for lots, homes, condos and businesses. We cover a relatively small geographical area, so it won't need searches by area. The twist is I need to be able to show some aspects of the property on the website, but then password protect other information on the property so that it is not available to just anyone. Here in Costa Rica you don't get a commission just by listing the property. Instead you have to actually bring the buyer into the deal. So most real estate agents here give some info on the property on their website and then give the potential buyer the exact location and other information once they arrive. I would like to be able to identify the potential buyer, check them out to make sure they are legitimate and then give them a password to access the rest of the information on the property. I want to be able to manage the site myself and upload new content once it is built, so there will be some "educational" time in this project as well.