I'd say you can use any Texteditor to do the job. Just select coherent blocks and move them in the desired position and change their rowposition accordingly.
This is a coherent block of one dicom node:
0|1|ECHO
1|1|iQ-WEBX
2|1|PACS
3|1|127.0.0.1
4|1|8000
5|1|Server
You see the second column which is filled with "1". This is the rowposition in the list. You can see the second column has an increased number topdown through the list. Thus you need to adapt this rownumber according to their new postitions to avoid trouble. don't touch the first one (0) as is the header of this table.
When you open the dicom.txt the dicom entries will be sorted 0-1-2-3-4 for example. After moving entries arround you'll have changed their order e.g. to 0-1-4-2-3. Bring the numbers in the second column in the rigth order again.
To make it foolproof, use the dicom settings to delete and enter the specific dicom nodes in the disired order.