The ICG is an interdenominational committee of two Reformed churches; the Christian Reformed Churches and the Dutch Reformed Churches. The members of the ICG are appointed by/on behalf of the General Synod or the National Assembly.
The rationale behind a single inter-denominational committee is that when working together to deal with disputes, independence and expertise are better guaranteed than with a dispute committee comprising only members of one's own denomination.
The ICG is there to deal with a dispute, or threat thereof, between members of the congregation and church council or pastor, or between pastor and church council. The ICG's task is set out in its regulations, which have been adopted by the church confederations concerned. Briefly, the ICG tries to restore peace by talking to parties and promoting mutual discussion, the aim being to see if a solution can be reached (it should be noted that the ICG is not an arbitration committee). The ICG produces a final report giving advice.
For more information, see the ICG's own website: https://icg-commissie.nl/.