Need to use customer country as Attribute in pricing strategy assignment

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Need to use the customer country as an attribute in pricing strategy assignment

Here scenario is that for All the European country customers ,if material is being shipped from  London BU then X pricing strategy will be applied if being sold from say RUSSIA/US etc. then Y pricing strategy to be applied, sold from India BU then Z . 

We have one solution of OM Extension to save the country to EFF on order header and combine it with Order Business Unit to derive strategy, but the derivation will come only on save.

Any other way e.g. by making use of standard algorithms