Validation list functions with two values

Im a novice at Excel who is trying to modify a validation list function to return a value based on two defined values.  My Form spreadsheet (sheet1) has an Item Type column (Col B) with a list of defined items to choose from.  Column D is listed as Manufacturer with a defined list based on the value selected in Column B Item Type.  Now I need the Item column C to list the corresponding items in the Non-Taxable Material spreadsheet (sheet3) based on the Item Type (Col B) and Manufacturer (Col D) values.

I was using this function in my validation list for the Taxable Material portion of my Form spreadsheet:

=OFFSET(Item,MATCH(B41,ItemCol,0)-1,2,COUNTIF(ItemCol,B41),1)

and it worked fine because each item had a unique list of manufacturers.

Now the same manufacturer under my Non-Taxable Material portion of my Form spreadsheet could have multiple item types.  I created the following named ranges on the Non-Taxable Material spreadsheet&
Col A header = Item1
Col A = ItemCol1
Col I header = MFID
Col I = MFIDCol

But I cant figure out which functions to use to get it to validate correctly due to how the columns are sorted.  Whether I sort column A or I, I get either the wrong material triggered by the item type or all the manufacturer material.

Thanks in advance!
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