Lisbon is 11 hours ahead of Honolulu

There is no standard 8-to-6 overlap. Someone joins early or late.

The 11-hour offset between Honolulu and Lisbon means there's no point hunting for a 9-to-5 overlap — there isn't one. Expect compromise: someone in Honolulu or Lisbon will need to take the call outside the usual 9-to-5, so share that load. Remember that Lisbon shifts for daylight saving and Honolulu doesn't, so recalculate the overlap after each clock change.