GPG asymmetric

I am trying to setup an asymmetric system between a couple of computers
I manage with gpg but am running into some problems when scripting a
tools which moves data between the boxes in a secure manor, I am use gpg
but would like to know if it is possible to generate a pair of key then
place the public keys on these computer while keeping both the public
and private key on the main server which will be sending the files, the
problem is on the remote computer they need to decrypt the files without
human interaction nor do I want to pass the passphrase on the command line.

Is it possible to encrypt on the master server and decrypt on the remote
computers just using the public key which is on them I beleive this
should be possible but when I try I still get prompted for the passphrase ?

Thanks

Henry