The easiest way to drive traffic to a custom social media website would be to input the Call to Action (image, icon or button) separately and link to that site. If the objective is to drive traffic there over other social media platforms then it would be advantageous to keep it seperate, as well as easier too.
If you're savvy enough, you could grab the HTML from the webview of a mailing that includes the social media block, tweak it, then input it into an HTML block. I would only recommend this if you have someone who clearly understands HTML in the email environment as it does create the potential for inconsistencies unless done correctly.
The safer option would be to get something custom designed from our design team (at a cost) who will be able to ensure that it's compatible, mobile responsive and renders consistently across mail clients. If that is something you'd be interested in, you can fill out our design form here and someone from our Design team will reach out :)
Hope that helps Barry! Let me know if you have any questions :)