Highlight the emails you want to track by selecting but not opening them. Select the Track in CRM button from the toolbar. Be aware that you will need to go back and set the various 'regarding' for the e-mail to track against the record you want in CRM. If all e-mails will track against the same record, then you can highlight them and select "Set Regarding" rather than track in CRM. This will track them and set them to the desired record in CRM.