You can add a new person with the name "Mustefa Jibril 1, Messay Tadese 2, Eliyas Alemayehu Tadese 3", or you can "Mustefa Jibril 1, Messay Tadese 2, Eliyas Alemayehu Tadese 3" with a person entry that is so far only been referred to by another name (such as a former name or an alias name).