Have a site which I want to build with SS. Done with plain HTML + CSS, but now I want to customize TinyMCE so that the content can be built in the same way.

The site has two columns (each 300px), with text or images. But for every new paragraph there will be a column break like:

P #1 | IMAGE (to P #1)
column break
P #2 | P #2
column break
IMAGE (to P #3) | P #3

In typography.css i sat p {width:300px;} and that was ok, both in the editor and frontend. But how to do more?
I tried to make a table, but that seemed to complicated for my users.
The text doesnt needs to flow through the two columns, but I really want the breake after each paragraph.
/Johan