So, Magento allows you to add multiple T&C's, you can add Multiple to fulfill your needs.
If a customer uses the checkout for the first time, you do not know in which customer group it belongs. You can obviously check if the vat id field is filled and add a small change.
- add two T&C's Customer and Bussiness
admin / Sales / T & C
- enable T & C
admin / System / Configuration -> Sales/Checkout
Now the users needs to accept them both.

Next up, setup automatic customer group assignment.
- enable Automatic Assignment to Customer Group
admin / System / Configuration -> Customer/Customer Configuration
- Select a group for valid Taxvat ID
We will add some custom extra code in app/design/frontend/rwd/default/template/checkout/onepage/review/info.phtml
<div id="checkout-review-submit">
<?php echo $this->getChildHtml('agreements') ?>
<?php /** ADD THESE LINES **/ ?>
<script type="text/javascript">
(function($) {
<?php /** Customer has business group id 2, 3(specify your own) ?? */ ?>
var isBussiness = <?php echo in_array(Mage::helper('checkout')->getQuote()->getCustomerGroupId(), array(2, 3)) ? 'true' : 'false' ?>;
$('#checkout-agreements ol.checkout-agreements > li:not(:first-child)').each(function(index, item){
item = $(item);
if (!isBussiness) {
// Hide
item.hide().find('input').attr('checked', true);
}
});
})(window.jQuery);
</script>
This way, customers will only see the first option and business users will have all the options.
Non business users will see only the first option.
