Question / Problem:
Can scripting be used to prevent users from merging two documents of different classes in Document Review?
Answer / Solution:
A merge operation, for pages or documents, can be cancelled via script.
A sample is available in the online help.
The online help in the scripting environment, "Help" on the menu bar and "Scripting Help..." on the pull down menu, brings up the online help in a browser.
In the browser with the online help, in the contents panel, expand "Configure Batch Operations" then expand "Edit Batches". This shows information on what events are launched when merging a document including a sample of skipping merging of documents if they belong to different Classes.