Seems a good idea. With three spaces of land and the aerial ropes, it seems fit. Current exhibit for one group, island for another, and Japanese island for another. How the rotations would work i have no idea but integration with siamangs could really help that. In an ideal world it would be cool to see the white cheeked gibbons a factor as well
Re. Orangutan groupings:
It would heavily depend on the personalities involved and the zoo would need to be prepared to adapt.
To use Auckland Zoo as an example:
They imported 2.2 juveniles in 1983 and 1984 that got on well together until the elder male reached adolescence and became aggressive to the juvenile male.
The two females (one of which had two offspring remain in the colony) remained on good terms until the elder female died aged 23 years.
An adult female and two adolescent females arrived in 2001, joining Auckland’s remaining adult female, her adolescent daughter and her juvenile son. This group of six initially got on well, with the males rotating access to this female and offspring group.
As the adolescents matured, conflicts began and the maximum number of females in any one grouping was two females from that point on.