Style definition with two variables

Hello everyone,

Is it possible to make a style definition dependent on two variables of a grid?

For exemple: I am in a situation that I am not able to create another property in my model. So, I want to make a State Definition that depends on two columns:

                             - Quantity Ordered

                             - Stock

                      I want to make my columns in the Stock change colors if less than Quantity.

Usually for resolve this problem I would create another property and give this property values based on my states. But, in this case I am not able. How can I do it?

Thanks