There u can use your exp if: your server x 25.
for2players = 50
for3 players = 75
for4players = 100
for5players = 125 or more.
There system works like that.
Exp/player
In my situation like that. My server is x20. Exp norm
[PartyExp]
PartyExp2Players = 120 // Party experience for 2 players...