Accessing domain shares on server from workgroup computers using domain user account

We have shares on our server which is on a domain. The shares is only shared to certain domain users.

Good.

I want work group computers not part of domain to access these shares with the domain accounts assigned to them.

As long as "accounts assigned to them" is a paraphrase for "domain users", I can't see any problem here.

Is that possible and how?

This is how it's meant to work by design. Users do have access to stuff they have access to, no matter what computer they use to log on. A computer is domain joind to manage the computer in addition to the users and their permissions.

I don't want give everyone permission, just specific users.

Just do that. Assign whatever domain users you'd like to whatever domain ressources you'd like.