One way is to make it a non-exclusive thing. Like how X1 was supposed to work out for the last 2.5 years of their run. So that way they can come back once or twice a year and continue getting exposure while also doing their own separate things to bring money to their agencies.
That might work this time. The only previous time it was actually tried was I.O.I and that backfired completely. I.O.I fans felt betrayed and tried to boycot the other groups and is claimed to be one of the attributing factors as to why none of the post I.O.I groups actually became big successes. But here the situation is a bit more favorable on that approach as I think the fans would be more willing to compromise to get IZ*ONE back.