Shared Channel setting folder permissions for external users

[jsieber_mt]

I've created a shared channel using B2B direct connect and I'm able to add the external members to the shared channel successfully. I understand that external users can only be added as members of the shared channel and can not be changed to owners. In the files tab, I need todefine certain users' access to all of the files and other users need full access to certain folders but read-only access to other folders. I'm not finding a way to do this. If I go to the manage access menu for a folder and try to define a specific external user, I'm getting the message: Your organization's policies don't allow you to share with these users. Go to External Sharing in the Office 365 admin center to enable it. 

External access is enabled at the Sharepoint level. Is it possible to define access permissions at the folder\file level in a shared channel?

[#2]

@jsieber_mt 

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