Assign a Task - Microsoft Outlook

Good Evening Everyone! 

Need your help on a really specific issue regarding task assignment on microsoft outlook. 

First, i classify my emails as "conversation" for a better tracking and follow-up, and to make sure that I always have a full picture of the discussion before answering. 

For those who know, this "conversation" features works with the email subject. 
So if i change anything on the subject, outlook will create a new conversation. 

My issue with task assignment is that it adds: "RE: " to the subject of all task assigned, and therefore creates a lot of new conversation in my inbox. 

I would like the subject to remain exactly the same as the email / conversation field. 

Is that possible and how to do it? 

Thanks for your help