I need to apply two discounts to a product

[jucuegas]

hi,
I have 2.6.10 and VirtueMart Joomla! 2.5.24
I need to apply two discounts to a product category.
What is sold is not a physical product but a course.

The same price is increasing with time. This I solved with several product prices. I always put the more expensive price and the discount will apply according to the date.

But I need to apply another discount, but should not be applied directly, but cart indicate the amount of the discount and applied in total.
That discount is that there is a fixed amount of the course must be paid in cash. As should not include the total price and is the quantity to be paid in cash.

I made a test in the form of tax payment, and that instead of putting a tax I put the discount. But if you buy two courses, only one discount will apply, so that discount should be applied per product or a category.

Can you help me?
thank you