item based encumbrance

Dear SCM Gurus,

Is it possible to have encumbrance based on item level.

I have annual budget. No carry forward. !

below is the scenario

Say i have a Blanket Agreement is for 3 years and for 1st year 500,000 2nd year 200,000 and last year 100,000

Currently i raise a request for 1st line with 500,000 which will be encumbered, returned when the blanket is created and simultaneously a release will be issued for this 500,000. (Ensuring this amt not spent for any other demand.)

In the same request line 2 AND 3 will be with zero, and in the DFF i capture this 200,000 and 100,000 respectively. for future reference. this is entered.