Good evening Gordon and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
I would love to help you with this topic.
I believe there are a couple of ways that you could work around this.
Whatever you do, you should use the global stock feature from Event Tickets Plus.
This will ensure that the overall stock is always kept “in check” while you are selling different ticket types.
This is untested, but here is a solution idea:
You could create a single ticket type and a ticket for a table of 8.
Once that is done, you could use a Product Quantity plugin for WooCommerce and edit the product in WooCommerce.
That way, you could force the “table” product to be a quantity of 8. That also allows you for a specific pricing.
There are several plugins out there, you might have to test a few to find one that works (e.g: https://wordpress.org/plugins/woocommerce-incremental-product-quantities/)
Let me know if that helps.
Have a great day!
Geoff B.