Access custom product attribute in grouped.html

I am trying to customize the grouped.html

I have placed a copy of the original file in the theme folder.

I am trying to access a custom product attribute. The name of the attribute is:

use_as_list_subheading

code fragment:

<tbody> <?php foreach ($_associatedProducts as $_item) : ?> <tr> 

in the loop I want to access the $_item which should be the list of items associated in the group product. I want to use the value of the yes/no attribute (use_as_list_subheading).

I am not sure if I am accessing it correctly since an IF statement using the attribute never returns true.

$_item->getUseAsListSubheading()

is what I am trying to use.

Am I trying to access the value of the custom attribute incorrectly?

Any help with the syntax would be appreciated.

My ultimate goal is if the attribute is true, I want to add style the <tr> so I can change its background color and the font color in each of the <td> in the row.