Please follow this article if you would like to create cascading filters within our Data View Plus web parts.
Option 1:
- Add 2 filter controls, one under the other.
- Filter the first one, and the options in the second one will be filtered
- Title before filtering based on assigned to:
4. Filtering by assigned to, then by title have less options:
Option #2
Same idea, but first level filter is done by using conditional formatting as a filter/categories.