POP/ROCK. This is Fort Apache (Fort Apache/MCA): Fort Apache. recording studio in Cam- bridge, Mass., has long been known as a breeding ground for the kind of cutting-edge, alternative rock that college kids crave. Here, they celebrate the debut of their own label with a 13-song sampler of some of their success stories: Throwing Muses, Dino- saur Jr., Buffalo Tom, Belly, Sebedoh, the Lemonheads, Julianna Hatfield, and more. The fare includes B-sides, previously unreleased tracks, and a few hits.