unless the world has moved on a real distance,
all you need is a couple of wooden, or aluminium channels
with either two or three channels inside, so it needs to be
between 40mm overall with a central upright, or
60 mm with two uprights.
apart from putting some rubber stops on the bottom of the doors
there is not much else used. the upper channel needs to be
deeper than the lower one, and you put the doors in
by tilting them and putting in the upper channel first.
since they are being retained at top and bottom, don't need
much more hardware.
in your case i think the real problem will be to ensure that the
glass on the outer doors is not proud of the space between it, and
the back of the middle door.
hope that helps
paul :wink: