Hi Tiago,
Thank you for your interest in Syncfusion Products.
I am afraid that I was not much clear with your requirement. Could you please let me know whether you need a Treeview like display with horizontal lines as described in the below image?
http://files.syncfusion.com/support/Tools.Windows/7.1.0.30/F80098/SampleImage.zipThe above display is designed using GridGrouping control. It is not a TreeViewAdv control. If I have misunderstood your requirement could you please let me know in detail of your requirement with a screenshot, so that we could work out in depth and provide you a better solution at the earliest?
Please let me know if any concerns.
Regards,
Fathima