WF to HR - One task to Specific User.

I am developing some workflows for the HR module, which was set up a table that selects those responsible for tasks RH_CENTRAL, RH_LOCAL and BP

Whereas to send a WorkFlow for the portal it appears in the Business Workplace 2 tasks equal responsibility, one that he takes the action and another just to view.

I'm putting the task as a Task General on TASK's, because those responsible need to be selecting this table.

I can not enter a User, position, unit or function sets in the task, because in this company, those responsible are moved frequently

What do I need: To make only one task is presented only to the official who was selected in the table, without which other people receive the same task.

Is there any way I can do that?

Thanks