is it possible to load data of one block in the tpl of another
I'm not 100% sure if this will work, but it's worth a try!

You may be able to use module_invoke to place block 2's content into the template of block one using the following code in your block-mymod-1.tpl:

$block = module_invoke('block', 'block', 'view', '2');
print $block['content']


This post might help to explain more, but for your needs you are only interested in the first and last arguments.  The first tells Drupal which module you're invoking, and the last is the block ID of the node you're looking to load the data for.