@JMichaelTX provides an interesting way to do it, and has the advantage of working with any number of words. Given your constraint for 2-6 words, you can use this regex:
([A-Z][a-z]*)([A-Z][a-z]*)([A-Z][a-z]*)?([A-Z][a-z]*)?([A-Z][a-z]*)?([A-Z][a-z]*)?
Just add a ? after each capture bracket that is optional.
