Hello Franck,
Good question. I’m afraid that Event Tickets Plus does not allow you to create product options for tickets. It creates tickets as Products and allows folks to add a ticket to the cart, but everything else after that is handled by the ecommerce plugin you are using for the checkout functionality.
So, if you are using WooCommerce as your ecommerce plugin, then it might offer a way to cross-sell products that have been added to the cart. In fact, I was able to find a WooCommerce extension that does that.
Sorry for the bad news, but I hope the WooCommerce extension will do the trick.
Does this help answer your question? Please let me know. 🙂
Cheers,
Geoff