The Multifighting Ability has become useless since CR2. There is no more multi-person interlock in CR2. Pls replace that branch of the tree with something awesome 
MultiFighting useless
2 posts · 2006-04-18 03:56:00 to 2006-04-24 03:28:00
Yes I think its a very positive use of what currently appears a redundant ability...let it give a defence or resistance buff to those in IL against the external free-fire activity....
If free fire attacks cant be isolated (as I suspect will be the case) then allow the ability to analyse the loaded buffs of the two combatants and buff the two resistances not in use for that IL.
ie
if an Ma IL with a gunman then multifighting adds a 20% bonus to thrown and viral defence etc
if a hacker IL with an MA then multifighting adds a 20% bonus to Ballistic and thrown etc