[LINK] "Line spectrum sharing" ? (Telstra offers separation proposal)

[Fernando Cassia]

In this story

Telstra offers separation proposal
Public prices, Chinese walls and ring fences
http://www.theregister.co.uk/2011/08/01/telstra_separation_proposal/

I read: "Telstra’s plan includes publishing reference prices for
wholesale fixed line services. The cost of regulated services – the
unbundled local loop and line spectrum sharing (used by retail ISPs to
connect customers to their DSLAMs)..."

Of course I know about local loop unbundling, where the local loop is
connected to other competitive player´s infrastructure co-located at
the incumbent´s central office, but it´s the first time that I read
about "line spectrum sharing". Can someone elaborate on how it´s
achieved in practical terms, or what does it mean?.

Of course I know what spectrum sharing is, on wireless communications.
I just can´t picture two providers sharing the same local loop, with
two dsl modems connected over a single copper pair.

TIA
FC