I am trying to create an order form - 

I have a Vendors, and those vendors offer items, which are stored in Vendor_Items form, using bidirectional (Vendor Items is a subform on Vendors). 

My subform in the Order Form for Items Requested has Vendors and Vendor Items. 

I would like to filter row.Vendor_Items by the row.Vendor, but ONLY IF a value is put into row.Vendor. If they have not put a value into row.Vendor, I would like all of the Vendor Items to be available.  

Is this possible? 

Any help would be appreciated!

Best, 

Steve