Hello @francis yau.

Thanks for reaching out. This is a difficult one since there is no real support today for this type of irregular shits. PagerDuty documentation includes examples for irregular shifts but this is not one of them.

To implement this pattern you need to use overrides. You can have two layers. The first with A and B in 3-week shifts and then create overrides for user C on every third week of the on-call shift. It’s a bit of manual work but you can try to automate this with our REST API.

In the meantime I’ll add this pattern as product feedback to our product team backlog.

I might be missing something, but isn’t it just a 6-user/6-week rotation with back-to-back weeks for users A and B ? E.g.