Consolidate ‘add-to-cart’ buttons into one ‘add-all-to-cart’ button

Maybe the Grouped product type is for what you want.

You can create a Grouped product and then add child products to it. A grouped product (with the child products) can be added by one click.

See WooThemes docs.

Edit:

If it’s not what you’re looking for, try to search for submitting multiple forms with jQuery (maybe this one), and have a look at this question about AJAX add-to-cart:

Woocommerce – Add a product to cart programmatically via JS or PHP

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)