Unit of measure should be different when we create the order for export customer

Hi Sd experts,

In our business scenario we have a material xyz. for this material we maintained unit of measure as KG in MMR.

generally we get orders as in quantity of 1000kg, 2000 kg etc.,

we have domestic and export customers,

my clients requirement is if we create order for domestic customers(using t.code ZDOM) Unit Of Measure is to be same as maintained in material master as KG,

but if we create order for export customers (using t.code ZEXP) Unit Of Measure should be in tonnes.

for example if user is creating order for export customer for xyz material for qnty of  10,000 kgs then system should allow to change unit of measure to 10 tonnes in sales order.

please guide me in this,

Thansk in advance.

shakeel