Specifying integration elements in mapping scheme

This is related to LN 10.7 setup.

I have created a mapping scheme where I want to specify mapping based on difference elements (item group, warehouse, sites). When I go to mapping elements, I can see only item group but no other mapping elements (warehouses, sites, suppliers).

The IDT is 10001074 (Purchase Order/Receipt)

I want to specify ledger based on item, warehouse, item group. Currently I can specify only item group as integration element but not other elements (like warehouse, vendor, site, item).

Can anybody guide me through the steps through which I can specify additional integration elements?

Vishal