Threads dot net should run within facebook container for firefox

Hi guys,

I wasn’t sure where to post this so I am posting here.
Facebook/Instagram/Meta introduced a new domain called threads dot net to compete against twitter about twelve hours ago.
I would like to see this domain (and everything it calls) automatically open in Facebook container for Firefox.
How does this work?

It is a tad annoying how you cannot manually customize what sites open in what container.

There should be a way for uses to force a site to open in the same container as Facebook.