At this moment it's not yet possible to set permissions per repository.
In the outstanding feature request https://jira.atlassian.com/browse/STASH-2643 it's stated:
We do have plans to implement finer grained permissions in the future
As a project manager, I have discovered that different developers want to bring their previous branching method with them when they join the team. Some developers are used to performing individual wo...
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG
You're one step closer to meeting fellow Atlassian users at your local meet up. Learn more about AUGs