in my implementation each released product has a default unit of measure CT and alternate unit of measure CFZ. 

In one CT there are multiple CFZ and the ratio is defined in the conversion unit definition of each product

My customers send purchase order either in CT or in CFZ. Of course any given customer sends the purchase order always with the same unit of measure.

To make life easy for my order entry team I would like to predefine the unit of measure in the new order form based on the customer.

Is this possible?

Let me know