Service Plan Item Calculation based on Items

Example:

I want to create service plan with Service plan Items for differnt categories.

CCTV maintenance charges is charged every 3 months for, charged for 30% of sale amount of CCTV items only.

Projector Maintenance will be monthly at 5% of Project Price.

So when I add the Service Plan Project Items, and add a calculated service plan, I get two filters, to apply calculation to the Service Plan Project Items or to all Project Items. Wuld be good to have ability to select products from either, so that I can have two service plan Items, one cakculating for CCTV items and second one for projector items only.