How to Record email by project name?

How to Record email by project name?

For example, I got 10 leads from my web form, and assigned all 10 leads to one sales person, I want only the lead related email show on each email section, by doing that, I will not mess up with all the other leads. 

However, when i check the email in each lead through CRM. the email under CRM seems record all the email by the email address, is there any way to make it project related?