I'm not sure if I am reading your request correctly. Are you looking to see how often users participate or how often particular members interact with each other (ex. how often the same two members interact)? My assumption is the former so I will base my reply on that.
LSI's Member report supplies information based on posts per day and Community Klout score. There is no way that I am aware of to filter out employees via that section of LSI. There are however other ways to get to the information you appear to be seeking. Your first option would be to use the content reporting in LSI and then select the members reports there and filter out employees from that report. In our instance we have roles assigned to employees and use that to filter reports based on if we want their activity.
Your second option would be to use Admin User Metrics where you can report on all sorts of user activity. You can also filter by roles in this report or download a CSV and do your own filtering in a spreadsheet. I like to convert the CSV into a table so I can filter as well as sort the information as I please. One caveat about the CSV is that filtering out roles can be more difficult if users have multiple roles assigned. The CSV will list each role in that field so you will have to be careful to filter any role combination that includes an employee role. So, I would suggest filtering by the employee roles in the admin role before exporting the CSV. Also be advised that these files can be quite large so don't be surprised if it takes a while to download. 🙂
Best of luck.
I would also suggest putting your support behind this idea https://community.lithium.com/t5/Product-Ideas/LSI-Top-member-filter/idi-p/197497
