conditional formatting on outlook calendar: categorize if external parties are involved

[pietro_tmb]

hello, I'd like to format appointments on my outlook calendar based on the fact that external attendees (with email domain different than mine) are invited. 

Does anyone have any idea how to do that?

the rule should be: if(attendees with domain different from mine are in the attendees string) then (category = blue), else (category = yellow).

thanks!

[#2]

@pietro_tmb did you find a solution to this ?