I think you mean that for any given record in the Job table you need to link to more than one record in Tasks, but that it is also true that any given task may need to be performed for more than one job.
Is that correct?
If so, you have a many to many relationship and you need a third table, a "join" table that facilitates the links between records in the two tables:
Jobs::__pkJobID = Job_Task::_fkJobID
Tasks::__pkTaskID = Job_Task::_fkTaskID
For an explanation of the notation that I am using, see the first post of: Common Forum Relationship and Field Notations Explained
A Portal to Job_Task can be placed on the Jobs layout to list all Tasks specified for that Job. A portal to Job_Task on the Tasks table would list all Jobs that specify that task. When you place a portal to Job_Task on your Jobs layout, you can include fields from Tasks in the portal row to provide information about that specified task.
With those relationships a text field (or a 4th related table) can be used to record notes about a task linked to a specific Job.