Expense CCID not generating dynamically

 I am importing  around 10000 assets from legacy system into FA_MASS_ADDITIONS table .Each asset is having different location id(Location Flexfield has four segments).I am populating expense CCID same(with a valid default value  say 131206)  for all these 10000 assets as i do not have all the different combinations  in GL_CODE_COMBINATIONS table.Now when i am running depreciation then all these 10000 assets are going to the default value of 131206 .What i want system to do is to dynamically create entry in GL_CODE_COMBINATION for the expense CCID based on the first segment of location id.What changes do i need to do in