Hi,
Yes, this is possible with cover eligibility. I'm not sure about sequential order, as the concept of this funcitonality is to create one pool of the budget (or as they are called 'groups'), based on the rules that you define.
However, did you consider budgeting only 1000, while posting could be done on lower level, e.g. 1000-01? In this case, you can achieve it simply with budgetary structure (or, alternatively, with AVC control objects).
Regards,
Eli
