Optimize similar referrers

Dear devs,

Your plugin seems great, I was deciding between various Google Analytics tools and I endeup using Koko!

One thing I noticed, though, is that it is somehow not convenient to track users who arrive from newsletters or services which use their custom links.

I would like to have the option to group referrers by their domain, a keyword, o something else.

See here an example of users who arrive from Email sent via SendInBlue service: https://gofile.io/d/FhkAwY

It would be ideal to group them in a single row.

Let me know if I can help further,
Thanks again.