How to show summary of ALL sales person's activitty by lead.

How to show summary of ALL sales person's activitty by lead.

Want to track every activity/call or customer contact by specific sales person associated with each lead over time.
So sales person A  had 6 calls, 5 emails, 2 meetings with LEAD B during a specific reporting period such as week or month. Any help with this multi level report and summary?