Cross Reference Two X-Y Tables that share the X Axis

If someone could please help:

I have the following two sheets (may lose formatting, see Attachment please):

Sheet 1 Sheet 2

Inventory Required Item1 Item 2 Item 3 Inventory Required Item1 Item 2 Item 3
Product Supplier
P1 X S1 X
P2 X S2 X X
P3 X S3 X
P4 X X X S4 X X

I want to create a Sheet 3 that automatically cross references the above sheets as such:
If a Product (i.e. P1) maps to an Inventory Required (i.e. Item 1) and an Inventory Required (i.e. Item 1) is mapped to a Supplier (i.e. S1 & S2) then the results would show which Product (i.e. P1) requires which Supplier (i.e. S1 & S2). It doesn't necessarily have to look like the graph below, a list will do as well, but it would have to be a sustainable/automated process seeing as how there are 200 Products/Supplies and 400 items that constantly change and are "re-mapped." Thanks for your help!

Sheet 3

Suppliers S1 S2 S3 S4
Product
P1 X X
P2 X X X
P3 X
P4 X X X X