Easy one
Google echannelizer for Windows or idreamx for Mac. Setup your IP address and in there you will be able to drag and drop channels in different bouquets. Once finished messing don't forget to sent it to the box
Harder
As its one large. You can ftp in to /ect/enigma2/
And in there, there will .tv files these are the bouquets
Copy it to you computer and edit it with a xlm editor and you can make up new .tvs too