AngularJS Form Validation inside an ng-repeat - validation

Question

So I am trying to validate the input of one item inside of an ng-repeat. For examples sake lets say that I have 5 items (1,2,3,4,5) and I only want to validate the form if the 4th item is selected.
I have used ng-pattern before to validate forms, but not one that had a dropdown menu to select item.name
I have included the regex I would like the 4th item to be validated with inside the ng-pattern.
<div>
<select name="name" ng-model="item.name" ng-options="item for item in items" required></select>
</div>
<div>
<input name="results" type="text" ng-model="item.results" ng-pattern="/^\d\d\d\/\d\d\d/" required>
</div>
Any suggestions as to the correct way to validate this situation would be greatly appreciated. I have thought about creating a directive to validate this, but that feels like is an overly complicated solution to this since I would not use the directive more than once in this app.
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It wouldn't let me answer my own question so here is the answer I figured out.
What I ended up having to do was use ng-pattern and pass it a function.
<input name="results" type="text" ng-model="vital.results" ng-pattern="vitalRegEx()" required>
Here is the controller code
$scope.item4RegEx = /^\d{2,3}\/\d{2,3}$/;
$scope.itemRegEx = function() {
if($scope.item && $scope.item.name === "fourth item")
return $scope.item4RegEx;
else return (/^$/);
};

Answer 1

or else...
add ng-change directive on the select dropdown which calls a Controller method and that controller method sets a flag whether to validate form or not.
eg.
<select ng-change="checkIfFormShouldbeValidated()" ng-model="item.name"></select>
// Inside controller
$scope.checkIfFromShouldBeValidated = function(){
if( $scope.item.name == 4th Item ) $scope.shouldValidate = true;
else $scope.shouldValidate = false;
};
$scope.formSubmit = function(){
if(($scope.shouldValidate && form.$valid) || (!$scope.shouldValidate)){
// Submit Form
}
};
See if it helps.

Answer 2

I wrote this recursive function inside my controller to check the validity of all child scopes.
function allValid(scope) {
var valid = true;
if (scope.$$childHead) {
valid = valid && allValid(scope.$$childHead);
}
if (scope.$$nextSibling) {
valid = valid && allValid(scope.$$nextSibling);
}
if (scope.scorePlannerForm) {
valid = valid && scope.myForm.$valid;
}
return valid;
}
Then in my controller I check this with the controller scope.
function formSubmit() {
if (allValid($scope)) {
// perform save
}
}