Linking contiguous copy into InDesign

Hello.

I have a job that has say 10 different paragraphs of copy turning into a lot of variants. For instance:

Letter 1 has copy 1, 2 and 3

Letter 2 has copy 1, 2 and 4

Letter 3 had copy 1, 4 and 8

Is there a way to import copy into InDesign and if it is edited externally, autoupdate and flow on from each other?

I know that i can paste Word files and link them but, you cannot flow the paragraphs on from one another. Im playing with InCopy at the moment but this looks the same.

Hopefully that makes sense.

Thanks for you time.

Warren.