http://dict.tu-chemnitz.de/dings.cgi?lang=de&noframes=0&query=ausgleichend&service=&optword=1&optcase=1&opterrors=0&optpro=0&self=1
or
http://dict.leo.org/?search=ausgleichend
Both know "compensational". What's the correct word?
The word I would choose to use to express the quality of someone who "to arbitrates between parties" is 'harmonising'. They actively work to bring about harmony between people. From a Buddhist perspective, 'harmonising speech' is a quality that will build community, by bringing people together. I like the word 'harmonising' because it suggests that this is an activity that needs to be done continuously. You can always have more, or deeper, harmony.
Hope that's not too off-topic!
Regards, Upayavira