Sharing Photoshop Libraries with External Partners?

We are creating Photoshop Libraries we would like to be able to share securely with our independent contractor freelancers who are not on our enterprose account. We can invite them, they can accept the invite, but from their end they don't see the lirary and from our end it says the invite is still 'pending'. What neother of us receive is any information about why this isn't working. 

Can anyone any shed any light on any setting we may need to adjust in order to make this workflow happen?

Thank you! -Sam