Something like this would require some custom coding, so it isn't something that is supported. I wouldn't recommend implementing this unless you're familiar and comfortable with writing php and MySql.
To have the price not be shown until you're logged in, you will have to emulate the behavior to check if the user is logged in or not at the top of the page. You would put an if statement around the price and show it if the user is logged in and then in the else display a message about having to log in to view the price or just leave it blank.
To have different price levels for different users, you will have to modify quite a bit of the query to get the price and information about the product. You will have to add some columns to the database table that store the different prices for different levels of user. You would also have to add to the backend admin section the ability to add these multiple prices in to the database.
