DSL modem design

I would like to design a DSL modem to operate on a industry specific cable as opposed to the standard telephone twisted pair cables. It has a bandwidth 1/10 th of the telephone cables. question:

1 can I use standard DSL chipset with reduced clock and components to limit the bandwidth?

Do I need to custom design with DSP and software ?

Are there consultants who specialize in this trade?

Raman