It depends partly on whether you want a fixed amount of space per
directory entry (and/or to align the entries vertically in the two columns)
If you don't, set up the main document as a Catalog. Use Format->Columns
to turn it into a 2-column document. Connect your data source and insert
the fields that you want, with an extra para or two at the bottom. Make
sure the paragraphs with fields on are formatted as "keep with next". Do
the merge to a new document.
If you do, you can either
a. try the above, but put your fields inside a single fixed-sized
table cell (you may need to adjust its vertical height to get this to
work). Don't put any space after it. connect your data source and do the
merge. Or
b. set your merge up as a label merge. Choose a label layout, then
either delete it, or keep one column if the cells are the right size.
Use Format-Columns to make a two-column document. Then add table cells
until the table fills the two columns. Then proceed as if it were a
label merge (i.e. one way or another, make sure that each cell except
the first has a <<Next record>> ({ NEXT }) field at the beginning.
Peter Jamieson
http://tips.pjmsn.me.uk