Exclude current page from perch_content_custom

Hi,

I'm trying to use perch_content_custom to get output from all children of a page, but without including the parent page itself in this.

I've tried to pass in the parent page url as a variable into the template and then filter directly in the template to only output when the current page doesn't match the parent.

<perch:if id="_page" match="neq" value="<perch:content id="current_section" />">

But that doesn't work.

If I hard code the value (below) then it does work, so perhaps it isn't possible to pass variables into a perch:if statement?

<perch:if id="_page" match="neq" value="/page-section/index.php">

Is there another approach I can take to achieve this?

Many thanks in advance for your help.