Group condition

Dear friends,

In pricing procedure i have conditions like packing and forwarding, suppler insurence, when select the group condition the price of the condition is not adding with net price, when i deselect the group condition check box the price is getting add up with the net price, can anyone please explain What is the functionality of group condition check in condition type of Pricing schema.in case of group condition check where does the value of condition type refelect

Thanks

ABBAS