Develop a specific Mac App

I would need this program to be able to login from several facebook accounts and stay logged in on all of them. the programs main point of emphasis is to be able to use a 3rd party site to watch, listen, click next and perform other options i will tell you directly. the 3rd party site would need to login by using facebook, other then that facebook isnt used just the initial installing of the "facebook app" i would need ASAP! If your able to do this or might able to with more info just message me!