File to multiple Idocs : how to design mappings

Hi experts,

I am designing a file to multiple idoc scenario.

I have 2 namespaces : one for the OUT with the datatypes, MT, etc... of my file and one for the IN with the external definition of the Idoc.

There's something that I dont get, it is how to design the mapping as I have two namespaces.

I have an example in which the mapping of the OUT namespace is from one MT to the same MT, but with a specific graphical mapping that uses removeContext --> sort --> SplitByValue --> field or removeContext --> sortByKey --> SplitByValue --> field. I don't really get the purpose.

Could you pls explain me how it works or how it should work?

Thanks a lot, any help would be appreciated

Regards,

Jamal