How to add multiple signitures to a file with PGP Command Line

It is possible to encrypt a file for multiple recipients. But is it possible and how is it done, to sign a file with multiple signitures (simultaneously) ?

pgp -es -r u1 -ru2 -s s1 -pass only signs the file with one signer key.....

With gnupg it is possible to to add multiple simultaneous signitures to a file....