roll your own impossible to expand 1st trigger automatically

hi i have a site that is not live yet i am using the following code with no issues , it functions well (fantastic plugin thankyou).
my issue is , i am using the roll your own as follows as i have 3 buttons placed horizonatal.

<span class="collapseomatic button2" id="item_one1" data-group="item-highlander"  Item 1</span> 
<span class="collapseomatic button2" id="item_two2" data-group="item-highlander">Item 2</span>
<span class="collapseomatic button2 " id="item_three3" data-group="item-highlander" >Item 3</span>

<div id="target-item_one1" class="collapseomatic_content" >content 1</div>
<div id="target-item_two2" class="collapseomatic_content">content 2</div>
<div id="target-item_three3" class="collapseomatic_content">content 3</div>

the only issue i have is i cannot force “item 1″ to be open by default , i have tried using expanded=”true” ,and also Collapse-O-Matic CSS Tricks .colomat-close .

I have managed to have item 1 open by default but it then makes item 2 and item 3 open under item 1 (always open) . i cannot get item 2 (or 3) .to replace the deafult open item 1.

is this possible atall?
thankyou ,and thankyour for a very usefull plugin.