Mapping the grouping no. in list qualifiers for across modifiers

Hi,

We have the 2 different 'Discount List' modifiers, both modifiers have same list qualifiers assigned in the grouping no. starting from 1 & 2 (Order -->Ship From - X, Y)

Modifier 1 & 2 - was assigned to the different set of customers in list qualifiers (Customer & customer name) 

While book the order for the customer which is mapped in modifier 2, system provide the both modifier discount which is defined in the modifier.

Actual should be customer eligible only for the discount which is mapped in modifier 1.

This issue is due to grouping no. assignment in list qualifiers in between 2 modifiers.

Anyone have the idea about mapping the grouping no. in list qualifiers, share your views will be helpful.