How to set up 2 discount modifiers for the same item and customer

I need to know how to set up 2 modifiers for the same customer and the same item.

We are on 11.10.2 of the apps.

The customer is set up for an EDLP discount for all items in a category for Q1. I need to set up an additional discount for the same category for just the month of Feb. So on the invoice it would show;

Price of item            $50.00

less EDLP                -  5.00       

less Feb Special      -  1.25

I have both modifiers set up but only the EDLP applies automaticall and the only way I can get the Feb Special to show up is to enter it manually. I need the Feb Special to apply automatically also.