Is there a way to merge Safari history databases?

Recently Safari had a glitch and wiped out my browsing history. I only discovered this after a couple weeks but had a backup that ran up to almost the day of the loss. I've restored the history from that backup, and would like to append the recent history since the loss. Is there a way to do that? Specifically is there a process I can used to take one set of backup files (History.db-shm, History.db-wal, and History.db) and merge them into another set?