How to filter in the ticket box depending on where it came from.

Hi, I'd like to know how to filter in the ticket box depending on where it came from. I manage 4 websites and each websites integrate with Helprace. So I'd like to sort out in the main ticket box by filtering tickets.

Example

Ticket from A@gmail.com ⇒ box1
Ticket from B@gmail.com ⇒ box2
Ticket from C@gmail.com ⇒ box3
Ticket from D@gmail.com ⇒ box4

I've read this guide but I didn't find what I want to know.

https://support.helprace.com/i91-searching-tickets-and-setting-up-filters

Thanks