FLAGing messages andset cusotm date

hello, I would like to ask if I can mark a message using FLAG and set my own date (I use it this way on outlook, when I simply sort which mails I have to “proccess” when) I attach a picture from outlook (translation from czech: DNES = TODAY, ZITRA = tommorow, TENTO TYDEN = this week …) outlook shows me list of "flagged: mail and group/sort it by date (this day, tommorow, next day…)