Today, this isn't possible. However, we recently announced a new feature at Microsoft Ignite earlier this month - I'm not sure if there is other public documentation yet, but it's mentioned here: https://ignite.microsoft.com/en-US/sessions/edb2bbb2-49a5-4df9-8744-1c9951f5f126
This feature is being worked on right now and we'll have a public update on this somewhere during the first half of next calendar year.
Separately, we (AAD Provisioning engineering) will reach out to BambooHR to discuss the opportunity to integrate with this feature.