Create a group, i.e. "Example"
Create a user that will be a member of group "Example"
Create an iBay is Read/Write accessible by the group "Example".
Now you have an iBay with restrictive access, accessible only by the group "Example".
Welcome to SME and I hope you enjoy. Be sure to read the manuals, as they will have many answers you are looking for, without having to wait for replies from moderators.