The Custom Calling features are essentially available on ALL real CO switches for most lines, unless there is a logical or other limit or conflict with its function. But a lot of the operating companies want to discriminate in what features are offered to different classes of service, like business or residence. Here in California, most of the telcos offer BCF and line hunting on residence class of service. But I found cable companies discriminating more offen on residence than the real telcos, especially COX!!! They won't let you order line hunting, so the only choice left is BCF.
Make the telco explain in detail why they can't or won't do it, when all 5ESS, DMS10, DMS100, DMS500, GTD5, and some others have those features, and the COS does not matter. Put them thru the paces, if you have a choice of another provider, you could threaten to change providers.
Good luck!
....JIM....