$scope.showAOptions = function(a) {
$('.a-options').hide();
$('.a-options-' + a.id).show();
};

$scope.cancelAOptions = function(a) {
  $('.a-options-' + a.id).hide();
};

<ion-content>
    <ion-list>
        <ion-item class="no-border"
                  ng-repeat="a in As"
                  on-tap="showAOptions(a)">
            <div class="item item-divider" ng-class="{'pending-resolution': a.pendingResolution}"> some code here that does always get displayed

            </div>

            <div class="item item-text-wrap a-options" ng-class="aOptionsClass(a.id)">
                ...SOME STUFF HERE...THIS IS THE EXPANDED PORTION
                <div class="row">
                    <div class="col col-25 col-offset-50">
                        <button class="button button-stable" ng-click="cancelAOptions(a)">Cancel</button>
                    </div>
                </div>
            </div>

        </ion-item>
    </ion-list>
</ion-content>