A way to Join lines but retain paragraphs?

I often need to join lines of text by doing: Selection > Join Lines (CTRL + J) in order to clean up page breaks.

Problem is, the raw text is already separated into paragraphs, so when I Join Lines all that goes bye bye, and I have to indent the paragraphs manually.

Or, I can select each paragraph individually and do CTRL + J, which is obviously tedious.

Is there a way to automagically join the lines for each paragraph somehow? Maybe there is a plugin I can use for this?

Or, am I using the wrong tool for the job with Kate?