TRACK DGs to set back on the require sender authentication

Hello,

I use Exchange 2007 and Linux.

My company might change the entire messaging environnement to Exchange but needs to indentify the distribution lists that need to be contacted from outside the company.

In fact as the linux sent mails go through the Edge, I could not activate the "RequireSenderAuthenticationEnabled".

So base on the 900 distribution list, is there any way to track daily or weekly the mails passign through the edge servers and sent to the 900 DGs?

I thought about extracting all the email addresses, copy them in a csv file and do a get-content + track mails based on that file. But I am not sure it is te right solution and how to constructed my script.

Can you please help me out?

Many thanks,
Graig