How to Add the action on Custom Object which allows to select the multiple targets.

We have the custom object list as below, on which we right-click for operation delete. We would like to delete the multiple objects at once.

Is there any way to handle this in vSpeher client 6.7 SDK.  The list does not allow multi-row selection. But if we don same for vSpehere core objects like cluster/host/VM we can do multi-row select

tried the acceptsMultipleTargets = true , but didd not work, Below is the extension point for action:

<extension id="com.xxx.snapshot.actions.deleteSnapshotAction">

      <extendedPoint>vise.actions.sets</extendedPoint>

      <object>

         <actions>

            <com.vmware.actionsfw.ActionSpec>

               <uid>com.xxxx.vcplugin.snapshot.actions.deleteAction</uid>

               <label>#{snapshotdelete.action.label}</label>

               <acceptsMultipleTargets>true</acceptsMultipleTargets>

               <delegate>

            <className>com.vmware.vsphere.client.HtmlPluginModalAction</className>

            <object>

                 <root>

                        <actionUrl>/ui/xxxx/index.html?view=remove-snapshot</actionUrl>

                        <dialogTitle>#{xxxx.deleteSnapshot.title}</dialogTitle>

                        <dialogSize>700,125</dialogSize>

                </root>

            </object>

          </delegate>

            </com.vmware.actionsfw.ActionSpec>

          </actions>

          </actions>

      </object>

</extension>