Read a file with 1 or more Interchange

Hi all,
First let me thank you for your wonderful and helpful library.
I started working in a company who uses EDI, and being curious I started playing with these messages, that´s when I found your library.
I´m no a programmer but attached is my attempt to create a dictionary for CODECO / COPARN / COARRI messages, that I share with you to use as you see fit. [EDI.zip](https://github.com/indice-co/EDI.Net/files/5778359/EDI.zip)

I hope you can help me with a petit challenge I have ... I´m trying to read CODECO messages from a partner from a file with one or more Interchange but I can only read the last one. Also the same partner mixes CODECO and COARRI files (in different files but on the same folder). This is a real example [codeco.txt](https://github.com/indice-co/EDI.Net/files/5778362/codeco.txt)

I need your help to:
- read multiple interchange messages in the same file?
- how to infer which grammar to use per file? In this case I´m doing a search the word CODECO or COPARN in the text before Deserialize ...

Also any comment on the messages is good...

Thank you again for your library

Start by reproducing the reported behavior with the attached codeco.txt file and review the library's deserialization entry point. Determine how multiple interchanges and mixed CODECO or COARRI files should be handled, then verify that the chosen grammar and every interchange are processed correctly.

Written by the indexing model from the issue text.