Where does the expression in and among itself come from? Is it only used for emphasis compared to in itself?
This would be interesting in and among itself.
The usual expression is In and of itself, used for emphasis, so the expression in your question seems unusual.
Could it be a deliberate mistake? We need to know the context.
For example, it seems ungrammatical to say among itself since 'among' implies more than one member of a group -- but does 'itself' refer to a group?
Context would help ....
Google search results for this bring up a lot of instances where it seems that it is a corrupted form of in and of itself and I think this is the case in the example given by the asker of this question.
In and of itself is just an emphatic form of in itself, meaning:
apart from any connexion with or relation to others; absolutely
The expression in and among itself, although rare in published works (9 hits on google books), can have a distinct meaning of its own. For example:
Unstoppable, it shoved us toward that mass of steel ribbon that curled around and around in and among itself like a gigantically long finely sharpened double-edged sword.
Here it means something like convoluted.