Since the board apparently no longer tells me these things, that is entirely up to you since it's pre-existing.
Also, it should be mentioned that I personally see a difference between a "___ part series" and a story with "chapters." Chapters should be all in one topic, but if there's a significant gap or, say, a three part series of short stories, that rule can be bent.
As far as your stuff goes, if you want it combined we can do that for you. If not... C'est la Vie?