Select all checkboxes on click of radio button

I have worked out how on clicking the radio button how to check a checkbox on my page, however this selects on the ID of the checkbox. The checkboxes on my page a dynamically generated with an id number on the end.

<input type="checkbox" certificate="false" id="gridcb0" siteid="23445" value="72278" class="custom selector"> 
Option One<br />

<input type="checkbox" certificate="false" id="gridcb1" siteid="23445" value="72278" class="custom selector"> 
Option Two<br />

<input type="checkbox" certificate="false" id="gridcb2" siteid="23445" value="72278" class="custom selector"> 
Option Three<br />

<input type="checkbox" certificate="false" id="gridcb3" siteid="23445" value="72278" class="custom selector"> 
Option Four<br />

<input type="checkbox" certificate="false" id="gridcb4" siteid="23445" value="72278" class="custom selector"> 
Option Five<br />   

<input type="radio" id="op5" value="1" name="options2" class="custom">
Select All

As you can see the IDs are gridcb0 to gridcb5 however the number on the end could go on in the hundreds.

Here my JS

jQuery('#op5').click(function(){      
    jQuery('#gridcb0').attr('checked', true);   
});

At the moment this will only select the top checkbox, how can change this JS so I cycle through and check all the required checkboxes?