Just so I can make sure I understand the use case correctly, you have
several extensions on the Yealink phone, and you only want that phone to
get MWI notifications for specific extensions such as line 1 and 2? You
want the phone to not be notified of voicemails on the other extensions
such as line 3 and 4?

William King
Senior Engineer
Quentus Technologies, INC
1037 NE 65th St Suite 273
Seattle, WA 98115
Main:   (877) 211-9337
Office: (206) 388-4772
Cell:   (253) 686-5518
william.king@quentustech.com