Client specific localization

Looking for advice for this tricky kind(for me!) of localization. We have different client in our project and we are making localization for client wise. Condition if client specific resx file is not available then it should take the default resx language wise.
We have folder structure like this :-
LocalizationFolder
     -en-us folder
          -Client1Folder
               en-us client specific resx file
default resx file
We have tried using getglobalresourceobject and getlocalresourceobject methods. These methods will go to till the last/deepest path in folder structure. But it is not picking up the client specific resx file. We have kept naming convention of resx file same for default and client specific resx file.
Thats why it giving error as 'default.en-us.resx file already exist OR it conflicts with other file'.
So my qu ...