JQuery :: Selecting One Block In A Collection?

I have a structure of similar blocks

- all containig a clickable image

- each identified by a unique hidden index

I want to find the value of that index when clicking on the image The code is something like :

<div class="bloc">
<p class="enTete">
<img class="modif" src="monImage">
<input type="hidden" value="1" />

[Code].....

How can i write the selector to read the right index when one the image is selected ?

Somethig like : (The '?' means I dont find how to do !!!!)
$(' ? .modif').click(function() {
test = $(' ? .index').val();
alert(test);
});