In the detailed view of an activity, under the Task Lists, there is a function to enable Task Prefix.
By using Task Prefixes, the tasks are better denoted to relate back to its parent Activity.
For example, the first prefix can be used for a zone number that the task is in, and the second prefix for the level of a building.
Task prefix will be applied to every task created under that particular activity.
Watch the video below to learn how to create tasks and add Task Prefixes to them: