Autocompleter without unique id

[eluser]neversummer[/eluser]
I am trying to implement the scriptaculous ajax.autocompleter in a recipe creation form. I have been able to get the autocompleter working, but not under the circumstances i ultimately want.

Again the context is a recipe creation form (brewing recipe, but a recipe nonetheless). One section of the form gathers ingredients in a certain category, I'll refer to as CatX. CatX can collect one or more ingredients and has 2 attributes for each ingredient:
- name (text control), qty

I want to use autocompleter on the "name" text control. the control has a name="CatX[name][]" so I can collect a number of them. to get autocompleter to work you must provide the text control with an id (id="catx_name"). Since I generally have more than one of these the id is not unique and therefore the autocompleter chokes. That is, the autocompleter works on the first control, but not the subsequent name controls.

I'm hoping someone has run into this before and could provide some insight on how to overcome it.

Thanks, mike