Software

And what type of OS is in use here?

It makes a difference

Being software developer, i would suggest to have a plugin for outlook or some other application secure one to stay on the server and use the default email gateway at its simplest form and trigger it based on your custom rules/settings. I hope there are lot of such available, but choosing best one is the challenge.

Any more details you know, respond or email me.

Search Google for Outlook plug-in offerings. A quick search found this site, which may have an app you can use for your purpose. I'm sure there are many other sites with similar offerings.
http://www.office-outlook.com/outlook-addins/automation.html

If you are comfortable writing code, try this DLL http://www.freevbcode.com/ShowCode.Asp?ID=109

There are many command line mailers that can be used in a cmd or bat file using the for command


http://www.petri.co.il/send_mail_from_script.htm

You can write some piece if VBA code for excel/outlook adding additionaly the option to track times/addresses etc...

We use WinAutomation for this kind of stuff. Saves a lot of time and effort and is especially suited for tasks like the one you describe.

have a look at http://www.winautomation.com

http://www.techrepublic.com/blog/window-on-windows/send-an-email-with-an-attachment-using-powershell/4969

You may be able to apply some of this to your situation.

I am only a customer of this product but really like them. Their email component is one of the most powerful I have used. You can use in almost any language and comes as ActiveX or .NET for Microsoft environments. The email version will allow you programmatically attachment these documents and email as an attachment. This and other inexpensive tools will add the option to compress them to a ZIP file to have a smaller attachment etc or each file could be sent individually. Finally, you can choose to send directly to any email server or write the emails out as files which can be picked up by most email servers and sent. The latter is optimal if the file is getting sent from a process that just ones once such as a web page and the email server is temporarily down for maintenance.