How to filter list in AngularJS by variable

I have what should be a very simple task. I want to sort a drop down menu in angular based off of a given parameter. Should be easy.

I make a call to a dataservice the returns some data like so:

"success" : true,
    "data" : {
        "this_status" : [{
                "DefNo" : "111*A",
                "Com" : "111",
}, {
                "DefNo" : "222*B",
                "Com" : "222",
}, {
                "DefNo" : "333*C",
                "Com" : "333",
}
];
        "this_info" : [{
                 "Req" : "MUST",
                 "DefCom" : "111",
}, {
                 "Req" : "NoMUST",
                 "DefCom" : "222"
}, {
                 "Req" : "MUST",
                 "DefCom" : "333"
}]}

My task is to make a list with all the DefCom values that also have an associated MUST value. I need to list "DefCom" numbers that have a "Req" that is "MUST", inside of a dropdown. So in my example, my dropdown would have values 111 and 333.

In my controller, I execute the call

   $scope.getDefCom = function(){
        MyAPIservice.getDefCom().success(function(response){
            $scope.info = response.data.this_info;
            $scope.infoList = $scope.info;
        });
        }

Where I have this factory:

angular.module('MyAPI.services', [])
  .factory('MyAPIservice', function($http) {
    var MyAPI = {};
    MyAPI.getDefCom = function () {
        return $http({
            method: 'GET',
            url: '/thisis/mylink/'
        });
    };

    return invoiceheaderAPI;
});

This works for my first initiative, make a drop down that will list DefCom numbers. However, next I need to filter them.

$scope.require = MUST in this example.

Inside my template:

<option ng-repeat="option in DefComList" value="{{option.DefCom}}">{{option.DefCom}} </option>

I tried doing a filter like so:

ng-repeat="option in DefComList | filter: {Req: $scope.require}"

However upon more reading I couldn't find anything where you can insert a $scope variable into a filter. Most of the suggestions leaned towards writing your own filter. I did this, using angular.forEach. My filter is below:

 $scope.filterDefs = function($scope) {
        var clrreturn = false;
        angular.forEach($scope.info, function(value, key) {
            if (value.DefCom == $scope.require)
                clrreturn = true;

        });
        return clrreturn;
    };

However, my custom filter is running before getting the results of $scope.info from the $scope.getDefCom function. This is throwing an Error: undefined is not an object (evaluating '$scope.info') before $scope.info is ready. I know that this has to do with promises, so I tried writing in deferred promises. However, this didn't work either, and I have gotten frustrated because this seems like it should be a very simple task and I might be making it way harder for myself than it should be.