I guess I'm unfamiliar with the "conditioning" you speak of unless it's for an analog or digital circuit. And a regular OPX shouldn't need any additional conditioning just so you have a span of wire between your sites..
If you just need a section of cable pair from site-to-site, with no office equipment in between, then using the "Off Premise Extension" verbage should do the trick.
Have you tried speaking with business customer service? They may be able to point you in the right direction in regards to ordering the correct feature/service. Often times the conventional residential CS agents aren't familiar with some of the more obscure terminology.