How to perform key signature verification

[Mark Sargent]

Hi all,
  I am developing a small gpg encrypted network. All participants must have
their keys signed by the network administrator.

Is there a command other than --list-sigs that I can use to verify and
ensure that a key has been signed by an 'admin' key.

I wish to perform this check when encrypting and decrypting to prevent non
authorised users gaining access.

All ideas, thoughts, suggestions welcome

Regards

Mark