PS double dependent requirements

Hi guru,

I created a project with several activities. I created WBS BOM with two materials tIhat need to be procured in advance.

I assigned FG to a network activity and the two raw materials to another ativity.

Now, if I run MRP, I have double dependent requirements about raw materials, more exactly one derived from FG and another one derivad from assignment to activity, In which way I can avoid this double requirements? I have to assign materials to activity because I need to use as requirement date, the activity date

Thanks

Regards

Raffaele