I've done this in the past and here's what I did:
- Create a dynamic distribution list that keys off of them being a manager in AD. How I did this may be different than how you do, but I was able to set it up based on them being in the "manager" field in AD...but I'll explain next...
- Update AD using the ERP info. This was done for me pretty rudimentary since our particular ERP system at the time didn't have great APIs/hooks to allow for straight syncing of the data. So for me it was an export from the ERP database into a .csv file. Then I had a script that ran nightly (in your case I guess every 10 minutes) that updated AD with the latest "Organization tab" attributes in AD like manager, title, dept, Company (we used it for location), etc. It did this based on keying off of their employee ID # in AD, which we key in for each new employee via the Helpdesk.
The nice thing is when you look in AD or at a particular user's info in Outlook you can see both their "Direct Reports" and who their "Manager" is.
And of course the dynamic distribution list itself checks to see who is and isn't a manager in AD.
NOW, as far as "GIMME THE CODEZ", that's a different story. I'd be happy to help, but I no longer work at that company and it is their intellectual property, not mine.
If you can look at direct syncing hooks/api's between AD and your particular ERP system, that's where I would go first. If not, the export > massage data > import into AD like we did works well enough on a schedule.