Group discounts vs. sales/drop prices

[syrovidis]

Hi, I just started with PrestaShop after many years with Zencart, but I solve similar problem. In our e-shop we use group discounts a lot. But the discount we count always just from basic price of products. Especially when there is same sale or price drop of product it's getting complicated, because we want to offer to customer always the smaller price. I show it on this example:

Group discount: 10%
Product A - normal price 1000, sale for 800 = it means discount 20%, price for group discount 900 ........... at this product we offer to customer price 800

Product B - normal price 2000, sale for 1900 = it menas discount 5%, price for group discount 1800 ......... at this product we offer to customer price 1800

Do you understand me what I want? Is it possible to do it? I hope yes :-)

Thank you for your answer!