I think you have multiple ways:
1️⃣ In Amethyst you can add a zap split. Like I did now. Disadvantage: Clients zapping from has to support it. (Snort.social and Amethyst supports it, not sure about others.)
2️⃣ Zap prisms https://app.makeprisms.com/
3️⃣ Make an lnbits account ( https://demo.lnbits.com ) , add "Split payments" extension, and put in the wallets you want payments to be splitted.
I know these options for now. 🤙