RasCanjero-
Self imposed exile
True taking out the leadership of a group will help a little but once the ideology is in entrenched like it is in Southern Somalia the group will never be finished off only remain dormant till they come back with new faces and more violence constant surveillance is required along with reeducation teaching the youth true sunni islam
Take out the leadership and they'll be like unorganised headless chicken for a while.
During that time you can easily pick them up without the need of a military campaign.
They currently work in cells so you can only catch them all once you find the guy who's in contact with all the cells.