Is it possible for a game to read two mice separately? Sure. It's not common, but it's possible.

The game "Lemmings" was ported everywhere in the early 1990s, but the original Amiga version supported two mice at the same time (two mice, two players, two cursors).

That's a rare example of a game that designed in some support for two mice, and that support was specific to one platform.

RHCP = Rocky Horror Chilli Peppers?

(your points are all good, I just found the abbreviations amusing)