The easiest solution I’ve seen was the ZapSplitter that nostr:npub1getal6ykt05fsz5nqu4uld09nfj3y3qxmv8crys4aeut53unfvlqr80nfm was testing. Looks like they took down their instance of it but here’s the GitHub below. 

There’s also a LNbits extension for splitting incoming payments but not sure about support for showing the zaps on your posts. 

https://github.com/getAlby/ZapSplitter