Hi Christa,
You should be able to get the functionality with an advance smartobject. When creating your smartobject in the designer you will select advance smartobject then in your methods you would add a method.
Browse to your service instance you want to use and select the method from the tree view. After the method is selected and you click on next you will need to create the properties you want. You could just hit create all from the toolbar. After you click next you would be shown the Service Object Method Bindings. It’s the list screen in the wizard.
On this screen you can add additional methods. So in here you will select add from the toolbar and browse to your next site and add a method from that site.
One important note is that the performance of this smartobject might be slow so I am not sure if this is the correct way forward for you to go.
I would rather have one central list where you store all your risk/issues. If different sites is not allowed to see the items from other sites you can filter them out. Just add a property to your central list to say from which site they are from and filter on that.
Hope this helps.
Regards
Jurie