Split content into multiple columns using more tag?

Why not just create a few shortcodes for what you need?

you can create columns for all kind of uses,,

add this to your themes function.php file..

<?php
function yourtheme_one_third( $atts, $content = null ) {
   return '<div class="one_third">' . do_shortcode($content) . '</div>';
}
add_shortcode('one_third', 'yourtheme_one_third');

function yourtheme_one_third_last( $atts, $content = null ) {
   return '<div class="one_third last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('one_third_last', 'yourtheme_one_third_last');

function yourtheme_two_third( $atts, $content = null ) {
   return '<div class="two_third">' . do_shortcode($content) . '</div>';
}
add_shortcode('two_third', 'yourtheme_two_third');

function yourtheme_two_third_last( $atts, $content = null ) {
   return '<div class="two_third last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('two_third_last', 'yourtheme_two_third_last');

function yourtheme_one_half( $atts, $content = null ) {
   return '<div class="one_half">' . do_shortcode($content) . '</div>';
}
add_shortcode('one_half', 'yourtheme_one_half');

function yourtheme_one_half_last( $atts, $content = null ) {
   return '<div class="one_half last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('one_half_last', 'yourtheme_one_half_last');

function yourtheme_one_fourth( $atts, $content = null ) {
   return '<div class="one_fourth">' . do_shortcode($content) . '</div>';
}
add_shortcode('one_fourth', 'yourtheme_one_fourth');

function yourtheme_one_fourth_last( $atts, $content = null ) {
   return '<div class="one_fourth last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('one_fourth_last', 'yourtheme_one_fourth_last');

function yourtheme_three_fourth( $atts, $content = null ) {
   return '<div class="three_fourth">' . do_shortcode($content) . '</div>';
}
add_shortcode('three_fourth', 'yourtheme_three_fourth');

function yourtheme_three_fourth_last( $atts, $content = null ) {
   return '<div class="three_fourth last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('three_fourth_last', 'yourtheme_three_fourth_last');

function yourtheme_one_fifth( $atts, $content = null ) {
   return '<div class="one_fifth">' . do_shortcode($content) . '</div>';
}
add_shortcode('one_fifth', 'yourtheme_one_fifth');

function yourtheme_one_fifth_last( $atts, $content = null ) {
   return '<div class="one_fifth last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('one_fifth_last', 'yourtheme_one_fifth_last');

function yourtheme_two_fifth( $atts, $content = null ) {
   return '<div class="two_fifth">' . do_shortcode($content) . '</div>';
}
add_shortcode('two_fifth', 'yourtheme_two_fifth');

function yourtheme_two_fifth_last( $atts, $content = null ) {
   return '<div class="two_fifth last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('two_fifth_last', 'yourtheme_two_fifth_last');

function yourtheme_three_fifth( $atts, $content = null ) {
   return '<div class="three_fifth">' . do_shortcode($content) . '</div>';
}
add_shortcode('three_fifth', 'yourtheme_three_fifth');

function yourtheme_three_fifth_last( $atts, $content = null ) {
   return '<div class="three_fifth last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('three_fifth_last', 'yourtheme_three_fifth_last');

function yourtheme_four_fifth( $atts, $content = null ) {
   return '<div class="four_fifth">' . do_shortcode($content) . '</div>';
}
add_shortcode('four_fifth', 'yourtheme_four_fifth');

function yourtheme_four_fifth_last( $atts, $content = null ) {
   return '<div class="four_fifth last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('four_fifth_last', 'yourtheme_four_fifth_last');

function yourtheme_one_sixth( $atts, $content = null ) {
   return '<div class="one_sixth">' . do_shortcode($content) . '</div>';
}
add_shortcode('one_sixth', 'yourtheme_one_sixth');

function yourtheme_one_sixth_last( $atts, $content = null ) {
   return '<div class="one_sixth last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('one_sixth_last', 'yourtheme_one_sixth_last');

function yourtheme_five_sixth( $atts, $content = null ) {
   return '<div class="five_sixth">' . do_shortcode($content) . '</div>';
}
add_shortcode('five_sixth', 'yourtheme_five_sixth');

function yourtheme_five_sixth_last( $atts, $content = null ) {
   return '<div class="five_sixth last">' . do_shortcode($content) . '</div><div class="clearboth"></div>';
}
add_shortcode('five_sixth_last', 'yourtheme_five_sixth_last');
?>

Then add some css to your themes style.css file

.one_half{ width:48%; }
.one_third{ width:30.66%; }
.two_third{ width:65.33%; }
.one_fourth{ width:22%; }
.three_fourth{ width:74%; }
.one_fifth{ width:16.8%; }
.two_fifth{ width:37.6%; }
.three_fifth{ width:58.4%; }
.four_fifth{ width:67.2%; }
.one_sixth{ width:13.33%; }
.five_sixth{ width:82.67%; }
.one_half,.one_third,.two_third,.three_fourth,.one_fourth,.one_fifth,.two_fifth,.three_fifth,.four_fifth,.one_sixth,.five_sixth{ position:relative; margin-right:4%; float:left; }
.last{ margin-right:0 !important; clear:right; }
.clearboth {clear:both;display:block;font-size:0;height:0;line-height:0;width:100%;}

then when writing a post use your new shortcodes to create areas for specific text etc..

[one_third]text here[/one_third]
[one_third_last]text here[/one_third_last]
[two_third]text here[/two_third]
[two_third_last]text here[/two_third_last]
[one_half]text here[/one_half]
[one_half_last]text here[/one_half_last]
etc...etc....

change all the function names to suit your theme, and edit any css to match your theme settings etc..

full source here
http://tutorials.mysitemyway.com/adding-column-layout-shortcodes-to-a-wordpress-theme/

Marty