I contacted ProConnect chat on this and the response was "Unfortunately you will have to manually re-enter the information. You have to make 2 separate returns". 

That seem like way too much additional work to re-enter manually so instead, I copied the original return twice and renamed the 2 returns, then checked MFS for each taxpayer and adjusted info for each taxpayer respectively. Still took some time but much less than re-entering all the info. You can use the MFS Comparison as a guide to make sure info isn't duplicated on both returns and assure and the numbers add to same amount on the original joint return. Hope this helps.