Send from Gmail through your ministry's domain, and forward incoming Gmail into Taifa Mail.
Verify your domain and create an Taifa Mail SMTP credential.
In Gmail Settings, Accounts, add your domain address and choose to send through an SMTP server: mail.govconnect.ke, port 587, STARTTLS.
To route incoming Gmail through Taifa Mail, add a Gmail filter that forwards to an address on your verified domain.
A native Gmail connector with OAuth, so you skip the SMTP setup, is on the roadmap.