Russian cosmonauts were actually trained using this. In cosmonaut training, it was discovered that the most successful crews were the ones that were best able to shower together.

No, not like that.

The old Russian plumbing wasn't particularly good, and as one team member changed the temperature of their water, the others would freeze or get scalded. The teams that negotiated this best -- often without speaking -- were the most likely to succeed in more complex tasks together.

As a result, they engineered an electronic equivalent that had them all balance individual needles against a shared circuit. Those teams that passed this test quickly were kept together.