I think this exhibit may have been part of the old Small Mammals House, which was demolished to build the Worlds Apart walkthrough.
For a time, the banded mongooses also lived in an enclosure in Familiar Friends with a visitor tunnel and viewing bubbles going through it. It was roughly opposite the giant tortoise house and has since been demolished.
They also lived next to the geladas, in a small enclosure that is now the waterfall by the entrance to the smooth-coated otters.
