Set filter in look up in sub form based on parent form input

Set filter in look up in sub form based on parent form input

I have a Purchase Order Form and Purchase Order Items form. Purchase Order items is a sub form in Purchase Order.

I have Supplier in the Purchase Order. In the Purchase Order items, i need to show the Products based on the Supplier selected in the Purchase Order.

I am not able to set filter condition based on input.Supplier. 

Let me know if this can be done.