Can i re-add the office 365 owners inside the sharepoint site collection admin

I have created a new Private sharepoint team site named "TestUserPer1", where by default i will get this group added as site collection admin:-

Now i mistakenly remove the above group from the site collection admin, so i tried to re-add it again, but the auto-complete did not return any entity named "TestUserPer1 Owners" ... any advice (i only get "TestUserPer1 Members")?

Thanks