Are your teams dependent or inter-dependent?
Dependency alone sets up a power dynamic that gets in the way of good cross-functional teaming.
Inter-dependency allows for power sharing - allowing both parties to share situational power. It's a healthier state.
When you charter projects or teams, look for ways to create interdependencies. If they don't occur naturally from workflow, you can create them with your reward structure. Examples include shared targets for bonuses and shared recognition for accomplishments.
Power dynamics are often overlooked in organizations but exist at every level. From your position as a senior leader, it's not enough just to model the behaviors that you want, you must also set-up conditions to encourage healthy interactions. No one else has the influence and authority to create, monitor and reward healthy, effective interactions.