Facebook problems

Hi All, Any help would be greatly appreciated with this issue. My aim is to block Facebook across our domain which i know i can do by blocking the category that it comes under of ' social.......' but the problem that i have is that within our company the marketing department and the rest of the organization needs to still access two fb accounts. these accounts are public so do not require login but i would like to block the rest of fb. I have thought of 2 ways to do this both of which i am struggling with. The first is to wildcard the url so ' facebook.com/xxxxxxxx*' but this doesnt seem to be working and the url changes from this as you browse the profile. The second would be to disable the login button or the ssl traffic coming from that page (Is this even a valid option?!) Many thanks in advance for any replies