236763 Google Map Change

I have a database with the locations of houses. I also have a database with the locations of points of interest (schools, parks, that sort of thing). I need a google map that will plot each of the houses on the map and then, when a user clicks on a category of groups-of-interest, those points will appear on the map as well. An example image of what I am describing is attached so that you can better understand what I am talking about. The first time that a user clicks on one of point-of-interest categories, the points will display on the map. The second time that a user clicks on one of the point-of-interest categories, the points should dissapear. Based on the examples provided by Google, I have built an example google map. Using a (already working) XML database connection, it is successfully pulling points of interest out of a mySQL database and plotting them on a map. I need the javascript created that onclick, will add the new points-of-interest onto the map. Each of the points-of-interest will have a different icon, so that needs to be implimented into the code as well. I have attached: An image to illustrate the front end A sample houses database A sample points-of-interest database A sample html file showing the basic front end for this project