In some instances it may be beneficial to break a large job into chunks, using iframes to combine all smaller bits into a larger whole.
One issue that arises with this however is the submission of that job data. 
Because the HTTP protocol only allows for 2 connections at a time:

http://www.openajax.org/runtime/wiki/The_Two_HTTP_Connection_Limit_Issue

We end up in a situation where only the first or second forms will actually submit.
The solution is we use JavaScript to create handler scripts in each satellite job, then issue a delayed submit command in the main job to each child form. 
These XML job files show this in action, be sure to load each job in the editor to see how it works!