Like the debate between longevity and peak, the answer would be both.
3 hits from the same release - is quite tough, since they themselves are their own competition blocking themselves from chart records.
Whereas hits in back to back comebacks, three times, is very good for the longevity of the group.
Between the two - multiple hits from the same album/EP is rarer than back to back hits. So I would say 3 hits at once.
Only acts who have achieved both might be able to answer for sure. IU and who else - Bigbang?