This would be a tricky scene to do, now that I think about it. Since most of Shakespeare's plays were presented on a three quarters thrust stage, I'll work with that kind of set up. I think doing a split level is the best way to manage this. Even if the people inside the gate aren't really higher up (or wouldn't be in real life) I would put them up above the heads of the other Antipholus.

I can't draw a picture here, but this is kind of what it looks like in my mind.

Antipholus, Dromio, (both of syracruse) Adriana, etc

Wall that rises up to their torso with a false wall that extends above their head. This could be like a frame of a wall, or parts of a wall (like a few places that the wall rises all the way, but still significantly see through for the audience.

Extra tall door that rises from stage level of the other Ant Drom pair to the height of the wall

Antipholus and Dromio of Ephesus.

The key thing here is that even though we can see each set of characters, they can't see each other.

Especially since the group on top of the wall has the "upper hand" in the situation, I like placing them higher up in the staging of things. When acting this out, I see the Dromios continuing to be the main presentational characters, but in this particular scene I see all the people within the wall hamming it up a little bit. In my mind, their really lighting into this poor fool who can't figure out his own house. Adriana might even be a bit frantic, trying to get this guy who claims to be her husband to go away. What must her "husband" be thinking!
I picture Antipholus of Ephesus and his party leaving in disgrace. Maybe some of the servants from up above would even be jeering over the wall.