Hi. CMYK color separation is a science all by itself, you'd need to learn and understand hardware color profiles, printing techniques and all that involves rasterizing images before they get printed. I'm afraid there is nothing built in in the framework for that purpose as it is a quite particular field of computer usage. Though, depends on your task you may come up with more or less acceptable results when you want to display a CMYK image. You'd probably want to elaborate on your question, because, otherwise the answer may be to generic and confusing.
Best. Oleg
