Hello @Abdool_Jhumka, unfortunately that is not possible. As far as I understand, Asana ensures that accountability for each task is clear. Thus, only one person can be assigned for a specific task. Perhaps, what you can do is create a project and have the 3 members join that project. This way, all of them can get notified for every new task (of course the notification needs to be turned on for this to work.) It will make it clear that all tasks assigned to that project are to be done by any one of them.
What do you think?
Now that I think about it, that’s precisely the purpose of the project (or at least how we use it!)
We have a project called Incidents. All incidents are put into that project, and initially it’s assigned under Backlogs section. Anyone in the project will know that there’s a new incident, and if someone is available to work on it, he or she will assign it to himself / herself and do it. The task is then marked as completed when done.