approach to landlords and property managment

i am in the process of building my buyers list. if I am looking to the newspaper ads to find landlord investors, my question is, what is the correct way to approach a landlord or property manager to get the landlord's information to find out if they are actively investing? should I just let them know I am an investor with discounted properties? how do I get past the property managers that don't want to give the landlords info to find out if they are interested in being on my contact list?