I think of an idea…
maybe you put in all those domains:
1. gmail.com (Gmail by Google)
2. outlook.com (Outlook by Microsoft)
3. yahoo.com (Yahoo Mail)
4. aol.com (AOL Mail)
5. protonmail.com (ProtonMail)
6. zoho.com (Zoho Mail)
7. icloud.com (iCloud Mail by Apple)
8. gmx.com (GMX Mail)
9. mail.com (Mail.com)
10. tutanota.com (Tutanota)
11. fastmail.com (FastMail)
12. hushmail.com (Hushmail)
13. yandex.com (Yandex.Mail)
14. rackspace.com (Rackspace Email)
15. 1and1.com (1&1 Mail, now Ionos Mail)
16. mail.ru (Mail.ru)
17. lycos.com (Lycos Mail)
18. rediff.com (Rediffmail)
19. tiscali.com (Tiscali Mail)
20. earthlink.net (EarthLink Mail)
21. excite.com (Excite Mail)
22. att.net (AT&T Mail, formerly SBCGlobal)
23. comcast.net (Comcast Email, Xfinity Mail)
24. verizon.net (Verizon Mail)
25. cox.net (Cox Email)
26. charter.net (Charter Email, Spectrum Mail)
27. netzero.com (NetZero Mail)
28. blueskymail.com (Blue Sky Mail)
29. airmail.net (Airmail)
30. inbox.com (Inbox.com)
Now, if
the system gets an email from one of these domains then
it would have to match the entire email address else
it would have to match the domain only.
and also there should be an option to make inputs to the domain list on your own.