Complex sentence: Volumes 1 through 6 of the series each featured at least one remix produced by the Ultimix remix service, a subscription-based company that produce and distribute special remixes of current hits exclusively to qualified disc jockeys, who adhere to their terms of service.
Split into simpler sentences: Volumes 1 through 6 of the series each featured at least one remix produced by the Ultimix remix service. This is a subscription-based company which produces and distributes special remixes of current hits exclusively to qualified Disc Jockeys, who adhere to their Terms Of Service.