Customer-Part Specific Sales Tax Exemption

Hey @knaderi,

I believe your best option is to use Entity/Use Codes for the applicable sales orders from that particular customer. See the following KB articles for more details about Entity/Use Codes:
Partial exemptions for California Tax Connect tax calculations
Exemption Overrides using Entity Use Codes in Tax Connect

Also, I suggest checking out this topic: Avalara and CA Partial Tax on MFG Machinery

Lastly, another option might be this: Create a Single use exemption certificate

Hope this helps!