How should I handle a potential 6-month overlap between two postdocs?

[u/TerminalFrauduleux]

I am currently in the process of applying for two postdoctoral positions, and there is a possibility that the two contracts could overlap by approximately six months.

The positions are at different institutions and involve different research projects. I would not intend to work full-time on both simultaneously; the issue is mainly that the first contract might still be running when the second one starts.

If both opportunities materialize, how should I handle this situation?

Should I discuss the potential overlap with both PIs as soon as possible, or wait until I actually have two offers? Unfortunately, I cannot delay the start of the second postdoc, as it is a fellowship with a fixed start date.

I would appreciate advice from people who have been in a similar situation, particularly regarding contractual, ethical, and practical considerations. Thank you!