When logging an email using the HubSpot Sales Chrome extension, you can select which records to associate the email with.
By default, the Chrome extension will automatically select the contact's first three associated deal records to log emails to. If you include any recipients in the CC/BCC field, the records' associated objects will also be automatically selected. To explicitly select which records the email will log to:
In your Gmail account, click Compose.
Enter the email recipient, the subject line, and the email body.
Select the Log checkbox.
To edit the record associations, click the dropdown menu next to the Log checkbox.
Select and clear the checkboxes next to the records you want to log the email to.
If you're sending the email to a recipient who isn't contact in your CRM, a new contact record will be created. You'll see the contact's email listed when editing the associations. Clear the checkbox if you don't want the email to log to the new contact record.