This has been accepted as a new feature request, but cannot be implemented until Toodledo implements support for this. Currently, third party apps such as ours cannot access the collaboration features.
Currently, the best workaround is to use Ultimate To-Do List’s multiple account feature. This allows you to link to multiple Toodledo accounts, and view and edit tasks on them. You can set this up in the Account Management area of the app’s settings. The unavoidable down side of this approach is that you must allow users access to your full account (not just specific folders). Also, your password must be entered on the other person’s device.