BRN-K is the largest, and best organized of the three, so the other two tend follow the big guy. BRN-K also has an extensive administrative organization, via the large number of Mosques and religious schools it controls. BRN-K has also spent years recruiting, indoctrinating, and training members. That's why mosques and schools are so important. The basic lesson taught is that Moslem and Malay (what most southern Thais are) is good, Thai and Buddhist (what most Thais are) is bad. BRN-K has also get its finances in order, having gotten thousands to supporters to make monthly donations (often only a dollar or two) to the cause. Drug and smuggling gangs have also been big contributors. This adds up because the BRN-K leaders not too corrupt, and the money does not disappear into their pockets. These resources have, over the past five years, enabled the BRN-K to form about 500 5-8 man cells (called RKK). BRN-K has provided from a few days, to several months, of training to at least one of the members of each cell. Each RKK unit is pretty independent, which makes it difficult for the police to get much useful information out of captured RKK members. Most of the RKK units are not very active, as there are only a hundred or so attacks a month. And in some cases, one RKK unit carries out several attacks a month. It's believed that only about 30 percent of the RKK cells are active. But the other 70 percent are still there, and still dangerous.
GMIP and PULO each appear to be less than a third the size of BRN-K, and are less active. So far, the three Islamic terrorist groups have managed to co-exist, and cooperate on some attacks. Many BRN-K members are also involved with criminal gangs. So despite the religious connections, many of the holy warriors make their livings with smuggling. Of course, that is seen as a respectable occupation in the south, unless drugs are involved. But a buck is a buck, and most smugglers will at least consider moving drugs across the border.
There are three groups of Islamic radicals in southern Thailand that comprise nearly all the active terrorists. These are: BRN-K (National Revolutionary Front - Co-ordinate, or Barisan Revolusi Nasional - Koordinasi), GMIP (Islamic Mujahideen Movement of Patani, or Gerakan Mujahideen Islam Patani) and PULO the Patani United Liberation Organization).