Inventory - Fast moving items, Slow moving and High value items

Hi,

 I need to know how can i make the ideal setup for this scenario

1. item which  are very fast moving and we need to maintain enough stock for them

2. Item which  are very slow moving, we want to keep only such quantity which will be sufficient for us considering the lead time

3. Few items which are very expensive, we want to keep an optimum quantity so that we meet demand   and don't  lock our capital

Another thing is about the Classification of items.

In my case each item is classified as

Group, Sub group and Category

Item001     GroupA           SubgroupA     CategoryA

Item002    GroupB           SubgroupB      CategoryB

Item003   GroupC           SubgroupC       CategoryC

and so on.

Groups are OK, but where can i specify the additional 2 classification

Thanks and regards

TP