Everything is bound by Asset. That is the sole deciding factor of where something displays. However some assets have stricter access controls. Specifically profile assets will check the profile owner for additional permissions. This means the shared album needs to have a non-profile based asset.
The best way to do this is to create the album within CB Gallery > Albums using a generic non-profile asset. So for example set its asset to "shared". Next you need to be sure your gallery can output that asset by editing the Gallery tab in CB > Tab Management and setting the Asset parameter to "profile,uploads,shared". This should display your new album and should allow anyone to upload to it since it won't be checking profiles for upload permission and will strictly use the create access parameters.
Note they will only be able to upload to the shared album from their profile. They can not upload to the shared album from someone else's profile.