Let\'s say I have the following (very simple) data structure:
$scope.accounts = [{
percent: 30,
name: \"Checking\"},
{ percent: 70,
name: \"Savings\"}]
You can check angularui library (ui-utility part). It has ui-validate directive.
One way you can implement it then is
On the controller create the method checkOverflow
that return true or false based on account calculation.
I have not tried this myself but want to share the idea. Read the samples present on the site too.