In theory I see no reason why this should not be possible.
First of all, it would help if you already used VoIP providers to call landlines/cellphones without involving Tor. Then you got the technical knowledge to set it up. Making it more complex by adding Tor to the equation will then get much simpler.
Since your calling partners are not using Tor, you need to either find a VoIP provider that supports TCP-only connections. I’d ask in some VoIP forum. Make it simple. Avoid terms Tor/anonymity, that would only cause confusion and divergent discussion. Tell them, you’re in a network where the firewall blocks all UDP.
Or if such a VoIP provider is difficult to find / doesn’t exist / hard to pay anonymously / etc. then use any regular (UDP) VoIP provider that you like and use a VPN to tunnel UDP over Tor. Related documentation:
I probably wouldn’t use the same VoIP provider both anonymous and non-anonymously so they’re not comparing previous VoIP recordings.
No way to use end-to-end encryption when calling partners are only using common devices (that don’t support VoIP encryption). Therefore make sure you know the warnings about voice recognition in the introduction chapter of the https://www.whonix.org/wiki/Voip wiki page.