I think it wont be necassary to merge user1 and user2.
You can just publish content in user1 and leave user2 empty.
User2 will then collapse and user1 will expand over the space of user1 and user2.
By the way, are you planning to use Joomla 1.0 or 1.5 with Vortex?
The Vortex template is not available in Joomla 1.5 version at this time.
Are you using the 1.0 template on 1.5 install? That will most likely cause the problem of the modules not collapsing properly. It is planned to release a Vortex 1.5 at some point, you can find more info here:
www.rockettheme.com/forum/index.php?f=52...v=viewtopic&start=15
If you want to use Joomla 1.5 you may have to wait for the 1.5 Vortex release or see if another template will suit your needs.