@Howard_Weinstein , @Malik_Dakdaki ,
Rebecca’s proposed rule would look something like this using a custom rule (Business plan and above)
You would have to setup one rule per person to achieve this. Note there is (currently) a limit of 50 rules per project so if you have many members then this may be limiting (apart from the manual work setting up all these rules and maintaining them). There is also a workaround if you need more than 50 rules. Hopefully this is something that will be solved with variables, perhaps coming in the near future. 
Similarly, but perhaps sooner, the People field should logically be soon available in Forms. To confirm, it is not currently available. (before you ask, I do not work for Asana, thus not aware of the roadmap which they do not make public).
If you can’t wait for all the above, you could create a single-select custom field with the names of all your members as the options of the dropdown question that can be inserted in a form. This field would populate your tasks from form submissions, therefore you could create rules that get triggered based on this custom field. Note, that the names of all the people in the dropdown will be visible to anyone using the form, which might be fine for internal use.
But depending on your use case, instead of showing people/members in the dropdown list of the form, you could ‘mask’ this to outsiders/clients by having them choose from a dropdown list such as ‘departments’ or ‘services’ - then you would have rules that for eg. trigger ‘HR department’ selected, thus add [members of HR] as collaborators and set [HR manager] as assignee, for example. Depends on your use case really.