Verify NT Credentials with PHP?

I assume this is impossible, but it’s worth a shot. I’m creating an app to use at work and I’d rather not have a separate user database which would force everyone to come up with a username and password. We have enough separate sites where we do this.

So if it all possible I’d like to verify their NT username and password. However I don’t have access to any of the company servers or anything - so even if it is possible I doubt I can do much - but here’s trying.