Late to the party here, but if you happen to still be looking for a solution, I’d suggest trying ConsignMint. We released the app earlier this year and it sounds like it could meet the need here.
With ConsignMint, you can easily track inventory, sales, and orders, as well as manage your vendors and track payments on an automated schedule that you set. Payment splits can be set per vendor or per product. You can invite your vendors to access their own dashboard where they can view details about their inventory, sales, and payouts — plus vendors can even submit products (or edits to existing products) for review. No spreadsheets needed.
ConsignMint does offer a free trial so there’s no commitment needed to test out the app. If you have any questions, let me know and I’d be happy to help answer them! Would love to hear your thoughts on the app if you decide to try it out.