How do you Store and Trust Signature Certificates Internally in a Central Location?

We are a small-ish Business with about 100 staff. We would like to start using Signature Certificates and trusting all staff Certificates on all staff machines. Is there a way to link these certificates to active directory or an easier way to input the trusted certificates onto all the computers. Because at the moment all I've been able to find is how to input them on individual computers. 1 trusted certifcate at a time. There must be a quicker way, such as to have a central place that can be looked up to on an internal network, in order to find out whether the Certificate/Certificates on the .PDF are trusted. So is there a way of doing this?

Also is there a way to make it so that if there is an untrusted Signature Certificate on the .PDF then it alerts the user in a very clear way?

Many Thanks

Dave.