How to resolve an *external* group email to individual emails?

I have a group email address, setup externally, and I would like to find out which emails are assigned to this group email.

IS this even possible? If so, how? I am a .NET programmer but willing to work with other language.

Let's say it's not possible because that information lives on external server. How would you do this in semi-manual / semi-automated? Send email to the group, request for all members of group to respond, then use some sort of outlook plugin / VSTFO to iterate through the replies to 开发者_如何学Pythoncreate the mapping?

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Depending on the particular setup of the server, you might try sending a large email to the group address. If their user limits are more restrictive than the server limit, the mail might actually get forwarded to the users, who cannot receive it. It's a long shot, but maybe you'd get a delivery failed notification from specific users...

If there's a chance of this working, do it anonymously...