1. Configure Google Gmail for Two Companies

Outgoing Mail (SMTP - Google)

Go to Settings → General Settings → Technical → Outgoing Mail Servers → Create.

Fill Required information and Click Test Connection → Save.

Incoming Mail (IMAP - Google)

Go to Settings → General Settings → Technical → Incoming Mail Servers → Create.

Fill Required information and Click Test & Confirm.

2. Configure Multi-Company Email Routing in Odoo

Go to Settings → General Settings → Companies → Assign correct email domain.

Go to Discuss → Aliases → Set unique aliases for each company.

Link each SMTP server to the respective company.

Ensure Incoming Email Servers fetch emails separately for each company.

2. Configure Odoo Standard Mail Server for Third Company

Outgoing Mail (Odoo SMTP)

Go to Settings → General Settings → Discuss → Outgoing Email Servers → Create.

Set SMTP Server: imap.odoo.com, Port: 993, Connection Security: SSL/TLS.

Use Username (Odoo email) and Odoo credentials.

Click Test & Confirm.

Thanks and Regards,

GrowingUpp

Grow with Us

Thank you :)

hi, 
if you want to configure outgoing and incoming email for each company , follow this link : 
How to Configure Outgoing & Incoming Mail Servers in Odoo 17
The video linkk : 

Hope this helps !