Samsung TVs suck when it comes to sorting the channel list. The work-around is to transfer the channel list to a PC and edit/sort it there. To edit the channel list on Linux, I found a tool called "SamyGO ChanEdit" quite useful. Downloadable via this link.
The tool requires SWT which is installed in /usr/lib/java on my system. To start the tool, used the following command:
java -classpath .:/usr/lib/java/swt-gtk-3.8.2.jar:SamyGO-ChanEdit-v54cd.jar gui.Main