Nth article and division

Hello everyone, hope someone can help me with this:
is there a way to publish only the Nth article of a section?
i know you can limit the number of them but don´t know if
just the 4th can be published.
And also can an article be truncated in size when published?
or divided in parts?.
Checked the manual and didn´t find anything helpful about
this... any help? 

Thanks to the dev team for the good work, its been a really
helpful tool for me