tricky questions, involves lot of assumptions, let us be brief

1. create Products a) Flour b) Sugar c) Cake (with BOM defined as Flour and Sugar) 

2. "Tracking" enabled for products a and b - set to "By Lots"

3. while in-warding the Flour or Sugar assign the Lot nos by easily identifying the supplier. For e.g Flour from Supplier A, assign the lot no as AFLR/0001, Flour from supplier B as BFLR/0001 

4. while consuming Flour or Sugar ensure to enter which Lot you are consuming

thereby at end of day when you check your "On Hand" quantity of Flour you can get what's the stock of Supplier A Flour and Supplier B Flour

Hope this answers your query, if yes click the upvote button please and mark this as answer

if not answered, elaborate your question much more with conditions / scenario , thanks

let's take the white sugar as example here, if you buy it from a single supplier you just name it white sugar in your system, in chase you take it from two different suppliers in the same time and you got a quantity from both of them you name one W.Sugar-A and the other W.sugar-B for example, with a different locations for  W.Sugar-A  stored in Room A 1st Shelf while W.Sugar-B is in Room A 2nd Shelf, you can do the using inventory model.
and let's the user know about the different between them.
i hope i did help solve your problem or at least give you an idea to Solve it.