I think it will be necessary to modify its here config/Character.properties
# PARTY XP DISTRIBUTION
# With "auto method" member is cut from Exp/SP distribution when his share is lower than party bonus acquired for him (30% for 2 member party).
# In that case he will not receive any Exp/SP from party and is not counted for party bonus.
# If you don't want to have a cutoff point for party members' XP distribution, set the first option to "none".
# Available Options: auto, level, none
# DEFAULT NEEDS TO BE VERIFIED, MUST BE CHANGED HERE AND IN CONFIG.JAVA IF NOT CORRECT
# Default: auto
PartyXpCutoffMethod = auto
# This option takes effect when "percentage" method is chosen. Don't use high values for this!
# Default: 3.0
PartyXpCutoffPercent = 3.0 <----- here
# This option takes effect when "level" method is chosen. Don't use low values for this!
# Default: 30
PartyXpCutoffLevel = 30 <----- and here