Is it possible to manage only a single row of a Form Editable grid view ?

Hello,

I got a simple form (editable grid view) and I would like to control only one row at time .
I got a select field about product item ID and I want to add the possibility to add a free description if the item is not coded .
I added a radio form field with Yes and Not and based on it I would to manage the Item ID field (YES) or the manual input field when (Not) selected.
On Ajax Event (on click and on change) I added this code. Item is the select item ID and item_descr is the Text field where to insert manual description.
If I add also into OnLoad nothing is visible…

if ({Coded} == ‘Y’)
{
sc_field_display({item_descr}, off);
sc_field_display({item}, on);
}
else
{
sc_field_display({item}, off);
sc_field_display({item_descr}, on);
}

It works but the problem is that “all” the columns of form have the same behavior and so they disappear on all rows when I choose NOT coded .
Is it possible to make something that works only on the active row selected ??
Thanks

editable.jpg