Complex sentence: Additionally Groscurth was active in maintaining communications between the anti-Hitler elements in Germany and the Chamberlain government where a deal was attempted to be made ensuring the Allies would not attack Germany if Hitler could be deposed.
Split into simpler sentences: Additionally Groscurth was active in maintaining communications between the anti-Hitler elements in Germany and the Chamberlain government. These communications attempted to create a deal with the British to ensure the Allies would not attack Germany if Hitler could be deposed.