How to set permissions on a file for a Mac without active Directory

We don't have our Macs in the Active Directory, we are looking to share an external hard drive to only Macs and not the Windows PC's on the network with out using active directory. I have tested sharing the external hard drive from a PC to everyone and both the PC's and Macs can access this, but we only want the Macs to see this and access this and not everyone. There is no selection for sharing with the computer name in the Share permissions so the only way to do this is to share it to everyone. The Mac accounts are local to the Macs and the PC's are on Active Directory so what i need to do is have a way to share this folder with only Macs and not all the windows PC's😕. Any solutions, any ideas will help

Thanks