Turns out you can add tons of routers. It's not as exciting perhaps as a room full of students, but the point does get across.
In one of my classes, in which I have 2 students, the two of them were on 1 router and I was on another. They shared some messages, and then I dropped in. One student quickly figured out that it was me. The other freaked out asking, "Who is 5.12?!! Who is 5.12!" It made for a good chuckle.
Laura, did you get your question answered? There's a widget setting that shows "all routers" which should should you the information you're looking for.