Arnis,
Thanks for your reply. I hadn't intended to "span" the paragraphs across columns. I simply want the material in the "x" flow to line up with the material in the "y" flow as needed.
My colleagues are using empty lines to manually line up the text in the left column with the text in the right column. The result is sloppy. I've been using table grids to line the two sides up. This makes the baselines line up perfectly, but it is hard to manage when I need to print just the right column.
To understand what I'm trying to do, imagine a training manual: the left column represents the instructor's lecture. The right column represents the material in the student workbook. The lecture needs to line up with the material in the student workbook, although some topics have several pages of lecture lined up against just a few paragraphs of student workbook material, while other topics have the opposite situation. Eventually, I have to print just the student workbook without the instructor's lecture.
I'm open to suggestions about how to go about this: tables, columns, text frames, etc. The only design constraint I have is that there must be two columns with the material side-by-side.