Have you set up aliases for your G Suite email account? If so, you can send mail from any of your aliases in addition to your primary email address.
The first step is to log in to your inbox and go to Settings.
Click on the Accounts tab and then on the link to add another email address.
Enter the address of the alias you want to use and leave the "Treat as an Alias" box checked, then click Next Step.
That's it! You'll see your newly-added alias on the Accounts screen. You can opt to always reply to messages from the address the message was sent to, or to always reply from your default, primary account.
Whichever option you choose, you can switch addresses at any time when you're composing an email.
If you want to add more aliases, just follow the same steps and you'll be all set to manage multiple addresses from a single inbox.