Multiple user/pc share same private key

Hi,

I am facing a problem on the PGP encryption, I need to encrypt the files with the vendor public key, then sign the files with our company private key (Only 1 key available) and send it back to the vendor.

However the tasks are decentralized to numbers of people/pc to do it. Is it the only way to import our company private key to each PC to allow different users to sign the files?  I have a security concern on import the private key to user PC.

Thanks