Suggest you enable your inital region only via iTC/Rights & Availability, then add more and open things up globally after two months.
The desired plan is to launch in only one region while at the same time taking pre-orders for the other regions. The Pre-Order feature doesn't appear to support this option.
I know this post is a year old now but did your release work as you initially planned?
I am looking to do the same thing, Live release in 3 countries for a month before a global launch while allowing all remaining countries to pre-order the app until the full release.
The iTC Help seems to suggest this isn't possible.
"Making your app available for pre-order removes other Version Release options from the platform version information page."