@JC2020 and @Magnito reference the rubberbanding approach above - that is key here. It is realisitcally the only way that will work IF your primsry goal is to be “physically with” people on the Zwift screen.
Assuming that is your primary goal, as people has mentioned, you can use dual recording to then achieve it, and therefore you don’t need SUF workouts to be ‘workouts’ in Zwift.
It would be something like this:
You set up your devices so that the trainer is connected to SUF first, in controllable mode if your use ERG, to run your workout in SUF. You start up Zwift and use a second ANT dongle or bluetooth to then allow Zwift to read the power output too (otherwise you won’t move on screen, but actually as long as there’s like 10W being produced you’ll move with the group anyway - more on that later*)
You and your friends either join a Group Ride where “Keep everyone together” has been set by the ride organiser, or someone creates a Meetup with that set (I’ve never done a meetup that way but I’m sure that was introduced)
Get zwift ready for the time the group meertup or group ride starts, and you can just start your SUF workout in advance so you’re moving.
Let the Zwift ride start on it’s own, and you can then chat away to your friends using your keyboard if that’s the ultimste goal.
Pro’s: You have a sense of group riding, abilityto chat while doing so
Con’s: The group will be at the pace of the slowest rider, so if someone soft pedals for any length of time at 10W, you’ll see that your’fre doing (say 200W) but moving t 5km/h. That can be a bit annoying puting out max watts and not ‘going anywhere’ (please no-one point pout its only a computer game)
Another con - when Suffering, we are often working so hard that trying to chat is tough - as that’s the point of the SUF workouts a lot of the time - but if it’s ‘easier’ ones or recovery ones obvs then that can work.
Hope that helps, fire away if any questions about two dongles, connectivity etc
For what it’s worth - for some testing I did a while back, I’ve connected four different apps at once (depends on your kit), so it’s all do’able having power picked up more than once.