Separate internal vs External approvals

We operate with 2 stages for our approval workflows, one for our internal team (where anyone can review and approve) and another for our clients via a shared calendar. The challenge right now is that the anyone can approve option allows our clients to approve it even if it's not ready for them. We've moved to using post drafts until sending to clients for approval, but having separate approval workflows that only show internally instead of the shared calendar would make this a lot easier.