CRM 2015 online enabled Server side synchronization with office 365 online Email. How to Sync only mails related to CRM contacts/accounts/leads from office 365 Mail to CRM online, but not all Emails?

Hi,

I am using CRM 2015 online and enabled the Server side synchronization with Office 365 Email.

After enabling, I am getting all the mails synced to CRM that are received in Office 365 Mailbox. I don't want to have all mails to be synced to CRM.

Instead, I am looking to have the mails synced from Office 365 to CRM online related to CRM Contacts/Accounts/Leads only.

Note: I don't want to use Dynamics CRM for Outlook add-on. As the users will be using Web mail only.

Any help would be much appreciated !

Thanks

Kiran