Inventory report - per supplier and

We are trying to find a solution to to help us in our ordering.

Part of our challenge is get an accurate picture of what we have in stock when we are preparing our next order with a supplier.

I need a report that:

1 - lists inventory of all items purchased by that supplier
2 - list alternative products supplied by secondary suppliers
3 - this list needs to be updated as new items are bought from a given supplier or those of the alternative products

Thanks for any suggestions, or guiding me to the right resources.