Resources with multiple calendars

Hi,

I recently create multiple resources and imported .pst files into them. The resources now have two calendars.

1. Can I merge the calendars? If so how can this be done?
2. I have given editor rights to the resource calendar via powershell: Add-MailboxFolderPermission PrivateRoom@dbigtest.com:\Calendar -User allusers@dbigtest.com -AccessRights Editor However user are getting a read only error when the try to edit the events. How can I assign this permission to both calendars for the resort?
3. If the calendars cannot be merged, can I copy one calendar into the other and decommission it?

Regards,

A. Singh