I guess every user landing from social media has some query parameters appended in URL.
If you use that query parameters to identify from which social media user landed on your website you can easily create audience based on that.
If someone is landing from fb it may contain utm_source=facebook you can cut out utm source value from url and store it in cookie until session expires and show experience to user depending on cookie value..(for ex. Facebook, Twitter, instagram etc.) This can be achieved using launch or maybe profile script