diff --git a/EgtMachKernel.rc b/EgtMachKernel.rc
index 9284f86..edcbc71 100644
Binary files a/EgtMachKernel.rc and b/EgtMachKernel.rc differ
diff --git a/MachMgr.h b/MachMgr.h
index cec5c7a..19a41ed 100644
--- a/MachMgr.h
+++ b/MachMgr.h
@@ -81,6 +81,8 @@ class MachMgr : public IMachMgr
       int  GetMachGroupCount( void) const override ;
       int  GetFirstMachGroup( void) const override ;
       int  GetNextMachGroup( int nId) const override ;
+      int  GetLastMachGroup( void) const override ;
+      int  GetPrevMachGroup( int nId) const override ;
       bool GetMachGroupNewName( std::string& sName) const override ;
       int  AddMachGroup( const std::string& sName, const std::string& sMachineName) override ;
       bool RemoveMachGroup( int nId) override ;
diff --git a/MachMgrMachGroups.cpp b/MachMgrMachGroups.cpp
index eb33df3..3235eca 100644
--- a/MachMgrMachGroups.cpp
+++ b/MachMgrMachGroups.cpp
@@ -61,6 +61,33 @@ MachMgr::GetNextMachGroup( int nId) const
    return nNextId ;
 }
 
+//----------------------------------------------------------------------------
+int
+MachMgr::GetLastMachGroup( void) const
+{
+  // verifica del gruppo base per le lavorazioni
+   if ( ! VerifyMachBase())
+      return GDB_ID_NULL ;
+  // recupero l'ultimo sottogruppo
+   int nId = m_pGeomDB->GetLastGroupInGroup( m_nMachBaseId) ;
+   return nId ;
+}
+
+//----------------------------------------------------------------------------
+int
+MachMgr::GetPrevMachGroup( int nId) const
+{
+  // verifica del gruppo base per le lavorazioni
+   if ( ! VerifyMachBase())
+      return GDB_ID_NULL ;
+  // verifico che il gruppo ricevuto sia corretto
+   if ( m_pGeomDB->GetParentId( nId) != m_nMachBaseId)
+      return GDB_ID_NULL ;
+  // recupero il precedente sottogruppo
+   int nNextId = m_pGeomDB->GetPrevGroup( nId) ;
+   return nNextId ;
+}
+
 //----------------------------------------------------------------------------
 bool
 MachMgr::GetMachGroupNewName( string& sName) const