gistfile1.cs

public override void OnInvoke(MethodInterceptionArgs args)
{
    try
    {
        args.Proceed();
    }
    catch (SqlException ex)
    {
        var terrService = args.Instance as ITerritoryService;
        if(terrService != null)
          terrService.AddModelError("Exception: " + ex.Message);
        var invService = args.Instance as IInvoiceService;
        if(invService != null)
          invService.AddModelError("Exception: " + ex.Message);
        
        // ... etc, for each service ...
    }
}