PGP Encryption using SubKey in a public key

Hello Team,

Need your help in finding a solution for a PGP encryption scenario for the below problem statement.

A file need to be PGP encrypted. We have a public key in form of .asc file. The public key can be accessed by opening the .asc key in notepad or WordPad. Generally to encrypt a file we create a public key account and use the public key block directly, and this works. But the catch in this requirement is that the “.asc” key contains a primary key and a subkey which can be viewed using any key generator application. Now the catch here is that direct encryption using the public key block wont work, we have to somehow use the subkey while doing the encryption. In snaplogic we do not have the option of selecting any primary key or subkey while creating the Public key account or configuring the primary key or subkey in the PGP Encrypt snap itself.

Can you please help in finding a solution for this.

Thanks,
Jiva