Conditional Data Validation

Able Excel Gurus,

I need your help here again.

From the attached, my source data is in columns AA - AD.
However, the inputs I want help on will be done on columns A and B.

What I want is to run a data validation on B which will be dependent on the brand selected in A. Column B should only carry the SKUs under the selected brand in A and not just all the SKUs.


Thanks in advance.