Basically it should be pssible but you need php/html coding skills and you need to know how to modify the nextgen gallery output. You need to create a thumbnail loop which outputs following code for each thumb
<div class="one_third">
<span class="framed framed_one_third"><span>
<a title="Aeroporto Venezia" href="http://lnx.cogesim.com/wp-content/uploads/2011/08/01.004-1024x768.jpg" rel="lightbox[grouped]" class="">
<img width="274" height="170 " title="Aeroporto Venezia" alt="" src="http://lnx.cogesim.com/wp-content/uploads/2011/08/01.003-274x170.jpg" style="opacity: 1; visibility: visible; display: block;">
<span class="lightbox_image " style="height: 182px; width: 286px; top: 1px; left: 1px;"></span>
</a>
</span></span>
</div>
and you need to replace the image link with your dynamic content (nextgen gallery thumbs code). I hope this helps you. I can't provide a "out of the box" solution though.