Hi, we had two connecting cat 5's in September, and we used Head Bands, you know the stretchy material kind.

This really worked well, and we put them back on our luggage to identify them at the airports. We bought these at the dollar store, and tried to find the brightest colors.
Our balconies were not opened, but you could talk to each other on either side, since we had three side by side rooms, only two connected, but with the three of our rooms, we were all chatty on the balconies (when we felt like it).
So, in reviewing my message, I really do not think I helped at all, since I am not sure if the room steward has anything, although I am sure they would try.