The Corporations
-MediTech
-Cyberware
-WWC Weapons Corp
-Armour
-Electronics
Hackers
The Media
The Independant A.I.
Schools
-Gunfighter
-Sniper
-Melee
-Stealth
-Psyche Agent
Mystics
-Empath
-Coercer
-Pyro
-PK
-Physical Adept
LAW
The Religion of War
The Highs
Chaos
Spiders
Individual Gangs
All Allegiances have values of what they think of groups. eg The Meditech and Cyberware MegaCorps are not the best of friends. Of course the other side may view things a bit differently. eg Most people allow the LAW more slack than the LAW would allow them, the LAW is in the greater position of power.
In the case of the large groups and their opinion of gangs positive values are the levels of technology they will have available (eg Gun 2 allows you to buy a Railgun) and the jobs they will trust you with.
The values each alliance has with other helps you to know who you are likely to called upon to defeat.
eg work for MediCorp and you know you'll probably have a few missions against Cyberware assets.
Political groups can continue to subdivide indefinately. Affiliation will default to the next lowest level.
eg You may be meeting 'Genuflect' a sub corporation that is part of the meditech alliance. You have never met them before but your Meditech alligiance is 2. So by default your alligence to Genuflect is also 2. Rewards may be down to specific level ie +1 to Genuflect or perhaps to meditech.
Affiliations with sub groups are usually their parent political group plus a modifier.
If a gangs affiliation with a parent is higher than the sub-groups, the base level is equal to the lower of the two values.
eg Being great friends with Medi (4) doesn't mean a sub-group trust you worth 4 if they only trust medi worth 2. You will also only start at 2.
For example a gangs affiliations may be:
The Corporations: 0
-Meditech: 2 Tend to work to assist meditech megacorp/doctrine.
--Genuflect: 3 (2+1) Have done a few quests to help Genuflect specifically. perhaps to the detriment of other meditech sub-corps.
---Genuflect VP of research: 4 (2+1+1) Your main boss
---Genuflect VP of marketing: 2 (2+1-2). The main internal opponent of VP(R)
Gangs: 0
-Negasonic: 2
--Dischord: 2, 2+0, sub gangs of Negasonic. neutral so default to Negas Value
--EarAche: 2
--BarrelHeads: 1, sub gang of nega but only have value of 1 for Negasonic themselves.