When my kids were younger we made a rule: no secrets from the family.
Unless, we were keeping a surprise.
We came up with this rule because we wanted to eliminate secrets that made siblings feel left out. As a team we would work together, not against each other.
It was a simple rule with a positive impact. It helped us to be open with one another, stopped anyone from talking behind someone's back and its a rule we would often hear our kids repeating to one another.
Knowing that secrets weren't being kept from each other was something that was important to us. We wanted our children to feel intimate enough with each other that they could talk things through during rough patches, instead of talking behind one another's back.
Starting this rule when the kids were young also had other benefits. It helped create a bond within the family that was cemented even when we were around others. For example, it taught them to be inclusive in situations when friends wanted to be secretive and push their sibling(s) aside.
Sometimes simplicity is all it takes to create a sense of closeness. Overall our rule of no secrets from the family has underscored the value of putting family first and has helped create unity among our children.