Front rotor/hub assembly stuck

Hey everyone, I'm replacing the front brakes (calipers/rotors/pads/lines) on my 1987 Z31 NA because the calipers are sticking, but can't separate the old rotor from the hub assembly - the two parts look as though they're one piece. I'm not kidding, I doused them with PB Blaster, scraped the metal where the two should separate with an etching tool, looked closely with a magnifying glass and bright light, and still can't see any discernible sign that two are actually separate parts.

So, short of using a jack hammer or explosives, can anyone give me some advice on how to get them apart. I've read the FSM, Haynes, way too many forums/posts from this and other Z31 sites but can't find any article/post/youtube etc., saying "if this happens, then here's what you do"…

Short history, I bought the car from the original owner about a year ago. He bought it for his wife, who didn't like it and wouldn't drive it. He kept it though and drove it sparingly, so it only had 67,000 miles when I bought it, and original everything. He had MOST of the records and receipts, but I can't find anything showing the front brakes have ever been touched.

Any help would be great, so thanks in advance.