Group Tasks in Salesforce - Facts and Fault lines

Group Tasks

Tasks which can be assigned to more than one user is called a group task. One can create a task so that up to 100 users are each assigned an independent copy of the task. 

To create a group task:

1. On the New Task page, click the lookup icon () next to the Assigned To field.
2. In the lookup window, select the Multiple Users tab.
3. Users can be organized into various categories such as personal groups, public groups, roles, or territories. In the Searchdrop-down list, select the appropriate option.
4. Optionally, enter one or more characters in the text box and click Find to search.
5. In the Available Members list, click one or more items to select them. Press CTRL+click to select multiple items individually, or SHIFT+click to select multiple adjacent items at the same time.
6. Click the Add and Remove buttons to move your selections between the lists.
7. When the appropriate choices are in the Selected Members list, click Done. If your selections total more than 100 users, you must reduce your selections before you can proceed.
8. On the New Task page, see your selections display next to the Assigned To field. The total number of tasks you are creating also displays.
9. Continue entering task details such as due date, status, and comments.
10. When you save the task, your selected users will be assigned copies of the task. Note that these copies are independent and not linked; they can be edited, transferred, or deleted individually.

Problem Statement
Elena is the practice-head of her  Salesforce competency and has to assign a task to all her team members to take their maintenance exams.
Elena notices that a task can be assigned to a role in a workflow.
Elena plans to create a Role of all her colleagues who have to take this exam periodically , she names it "SFDC Competency" and assigned this role to all the users who take these exam periodically.
Elena planned to create a Learning Activity Custom object on which she create a workflow which will create a task for taking exam assigned to all the users who are assigned to the "SFDC Competency" role when she creates an instance of Learning activity Object.
Issue
When she tried to test the rule she noticed that only a single  task was getting created and was getting assigned to the creator of the "Learning Activity" object.
To test the issue further she removes all users from the "SFDC Competency"  and leaves a single user.
Then she tests it again - now she finds that a task gets created and is assigned to the user of the single user in the "SFDC Competency" role.

Analysis

In gist, there's no neat feature available in Salesforce for assigning Group tasks via workflows. But there are some workarounds that can be built to accommodate the business needs. As of now Salesforce does not recognize multiple people assigned to a role in a workflow. When there are more than a user assigned to a workflow task assignment rule, it will instead send the task to the rule initiator and not the intended recipients. You can create multiple roles and assigned single person to each one. alternatively, one can have each workflow rule to have multiple task assingment rules one for each role.

But this may not be a good solution from house-keeping / maintenance point of view , what when user leave or new users get added.

Will keep looking for a better and more automated solution.