Table formats and best practices

Hi,

I am curious about best practices

Scenario:
Want to be able to track group task and personal tasks

Details

1. Group tasks are independent of personal tasks
2. Group tasks can be assigned to a person
3. Task assignments are only at the group level
4. Personal tasks are automatically assigned to that user
5. Personal tasks only apply to that person
6. The columns within the tasks table would be identical for both personal and group with exception of the ID (group/user)

Im curious if it is better practice to great three tables like so

tables

1. entity type (ex: 1 =  group, 2 = user)
2. tasks -> add an additional field to compensate for entity type
3. tasks-assignments

Or to separate the tasks table into two tables one for users and one for groups (assignments would only be associated to the second table)

Thanks in advance!!