I have three 'multijob' jobs: A, B and C
Job A has several steps. It executes A1 job, does something else (like a groovy script or env var injection step), and then A2, and then something else (another env var injection step).
Job B has several steps. It executes B1 job, does something else (like a groovy script or env var injection step), and then B2, and then something else (another env var injection step).
Job A is set to manually trigger job B

In my delivery pipeline, I have this setup:
[A] ----> [B]
[A1] [B1]
[A2] [B2]

See screenshots.
In this scenario, one should not trigger A1 and A2 separately, it has to go from the top level job A, because there is some logic within A that has to be executed before or after A1 and A2. Same for B.
Therefore rebuild button should only be displayed for A, B and hidden for the subtasks. Of course this behavior can be configurable.