Identifying Clients in Mutual TLS Using CN and Tenant ID

Identifying Clients in Mutual TLS Using CN and Tenant ID

I’m setting up mutual TLS authentication and need to identify clients using both the Common Name (CN) and a unique Tenant ID. What attribute should I use to include the Tenant ID in the certificate, and how should it be structured?

Edit: If I'll use the SAN field, which attribute would be the most suitable?

I already tried "Other name" but it forces me to supply OID.