Send and Track to Multiple Recipients with Outlook Plug In

My Sales team has requested that we look into using Marketo to help them send email blasts and get tracking on opens and clicks. 

We use a boutique CRM that is not integrated with Marketo and does not provide a solution to this problem. 

It seems as though the Marketo Outlook Plug-In could potentially solve this, but in testing I've run into the issue of only getting tracking for the first recipient (and all activity being attributed to that person's record). Some of our sales reps have email lists with dozens of recipients, so if we can't get tracking for multiple recipients it wouldn't address their request. 

Does anyone have experience fulfilling a request of this nature? Is there any workaround to use the plug-in to track activity for multiple recipients? I'd like to avoid having the Sales people send from Marketo themselves if I can.