Multiple newsletters email senders on same mailgun domain

Hello there, I rewriting this post cause I thought the fix was easy. I have a second newsletter for a specific context and I want to use my new hexonet domain for it, everything is configured but I’m afraid DKIM and SPF can’t work on different domains. So I wonder if there’s a way I can get rid of the via even if my domain is a different one? (or can I host 2 mailgun domains on Ghost?)