First, you will need to enable less secure apps.
From within your GSuite account, click the 9 dots in the top right corner, then Account.
On the left navigation panel, click Security.
On the bottom of the page in the less secure app access panel, click turn on access.
Then, make sure less secure apps is switched on.
Now with less secure apps enabled, navigate back to your Gmail account, click the gear wheel in the top right and then settings.
Click Accounts and Import, then click Add another email address.
Enter your first and last name and the email address you'd like to send as from your GSuite account.
Leave the "Treat as an alias" box checked and click Next Step.
Use smtp.gmail.com for SMTP Server on Port 587.
Enter your eXp email in the Username field, and your eXp GSuite email password in the password field.
Click Add Account.
Now open your eXp GSuite account and look in your inbox for the Send As code.
Enter this confirmation code in the pop-up window for the personal email to verify the account.
All done! Now when you compose an email from your GSuite, you will be able to select the email address you just added in the compose from drop down menu.