Restricting Custom People Picker to only one Sharepoint group programatically

Refer the following script files in your page,

    <!-- For People Picker -->

    <script type="text/javascript" src="/_layouts/15/clienttemplates.js"></script>
    <script type="text/javascript" src="/_layouts/15/clientforms.js"></script>
    <script type="text/javascript" src="/_layouts/15/clientpeoplepicker.js"></script>
    <script type="text/javascript" src="/_layouts/15/autofill.js"></script>

    <!--- -->

Now we have to create a div for our custom people picker control


    <div id="dvPicker">
    </div>

Now paste the following script which can restrict the custom people picker for one group.
Here we have to pass the Group name to get the corresponding Group ID

<script type="text/javascript">

        var reviewGroupId;

          SP.SOD.executeFunc("clienttemplates.js", "SPClientTemplates", function () {
            (function () {
                LoadInitial();
            })();
        });

     
        function LoadInitial() {
            var requestUri =_spPageContextInfo.webAbsoluteUrl + "/_api/web/SiteGroups/getbyname('Board')";
            $.ajax({
                url: requestUri,
                type: "GET",
                headers: {
                    "accept": "application/json;odata=verbose",
                    "content-type": "application/json;odata=verbose",
                    "X-RequestDigest": $("#_REQUESTDIGEST").val()
                },
                success: onSuccess,
                error: onError
            });          
        }

       function onSuccess(data) {
         
            reviewGroupId = data.d.Id;
            alert(reviewGroupId);
            initializePeoplePicker('dvPicker', reviewGroupId);

        }

        function onError(error) {
            alert(JSON.stringify(error));
        }

        function initializePeoplePicker(peoplePickerElementId, Id) {

            var schema = {};

            schema['PrincipalAccountType'] = 'User,DL,SecGroup,SPGroup';

            schema['SearchPrincipalSource'] = 15;

            schema['ResolvePrincipalSource'] = 15;

            schema['AllowMultipleValues'] = false;

            schema['MaximumEntitySuggestions'] = 50;

            schema['Width'] = '280px';

            schema['SharePointGroupID'] = Id;

            SPClientPeoplePicker_InitStandaloneControlWrapper(peoplePickerElementId, null, schema);

        }      

    </script>

Here we are restricting the people picker for only one SharePoint group "Board".
Apart from this group other group users will not resolve in this people picker.

Thanks,