SSH with multi-factor authentication

The customer requires us to setup MFA for SSH sessions. I have successfully tested MFA using Google Authenticator by following this article: https://www.linode.com/docs/guides/how-to-use-one-time-passwords-for-two-factor-authentication-with-ssh-on-centos/ . However, the problem is that other staff member need access to the system also. They can contact me each time for a verification code but I would rather not do this. I can create multiple accounts and setup up MFA for each person. This would mean they have to be physically with me or I can get them to scan the QR code through Teams. It just means there's a lot of administrative effort on my end. I have thought of SMS to groups but not sure if this is possible though. I think this is a little less secure but saves a lot of effort on my end. Is this a possible alternative? Any other suggestion on what I can do to solve this problem?