Configure Exim4 to perform MX lookup for outgoing email instead of delivering to local mailboxes

My mail server (VPS) was setup using VestaCP and has multiple domains -- it's only a mail server, not used for web. The server is running bind9 but all domains namservers are set to CloudFlare. Some domains are used to send outgoing email only -- these domains MX records in CloudFlare are set to a third party provider like Google Apps/G Suites. Some domains are used to send and receive email (as a real mailbox) -- these domains MX records in CloudFlare are set to the VPS. Example: - [login to view URL] is using CloudFlare nameservers. It's MX records set to Google Apps/G Suite. - In G Suite we have 2 email accounts: james@[login to view URL] and tom@domain1.com. - On the VPS, we have an email account notifications@domain1.com. - When email is sent from notifications@[login to view URL] to james@[login to view URL] using the VPS SMTP, exim will try to deliver email to the local mailbox james@domain1.com. All I want Exim to do is check/honour the MX records for domains its sending email to and deliver using the MX records set by DNS. The ability to send and receive email should not be impaired. The servers security should not be put at risk (i.e. open relay). Server access will not be provided. I will provide Exim's configuration files for you to edit and send back. Please only offer if you know what you are doing and not if you rely on Google (I could just do that myself).