We're currently using Trello to track our scrum based software development. We have a few clients which have access to different boards on Trello. Managaging the tasks between boards has become cumbersome. In an ideal situation we'd like to have one board in which we track all tasks on which we can then assign categories. These categories can then be used to give certain clients filtered access based on the categories.
Does anyone know of a piece of (preferably cloud based) software that does this?