You may change the Stock group 1 and / or 2  for selected stock item(s). 

TurboCASH4 - Stock items - context menu - groups

To change the Stock group 1 or Stock group 2: 

1.On the Edit → Stock items (Stock list screen) select the stock item(s), right-click on Stock group 1 or 2 context menu. 

If you need to select multiple stock items, press the Ctrl key and click on each stock items.

2.Select "Empty" or the available Stock group from the sub-menu. The Stock group 1 or 2 will change on the reports.