HTML::Template::Expr->register_function(box => \&box);

sub box {
   #read in other templates to costruct table header
   #use parameters to decide if it is the start or the
   #end of the box and what title to use etc.
}

##</code><code>##

<!-- TMPL_VAR expr="box('box-start','Table title')" -->
  table contents here
<!-- TMPL_VAR expr="box('box-end')" -->