New Child Page need to be created for two different pages

Need to create the structure like following :

Releases (space)
– Release1.0(page)
– Test(page)
– Development(page)
– Design(page)
– Release2.0(page)
– Test(page)
– Development(page)
– Design(page)

After I'd created the Release1.0 and Release2.0 under Releases space, i m trying to create new pages Test, Development and Design under Release2.0 (Release1.0 is success). But when I created for Release 2.0 the Parent is grouping under Release1.0 itself not under Release 2.0.