Create Parents / Children Relationship between different post types checking one or more parent.
Before starting, you have to create your Custom Post Type with an plugin or coding wordpress with register_post_type. I created: Selos.
I added a post type Selos.
I chose two custom post type as parents, jacuzzi_banheira and jacuzzi_spa.
Opening the cutom post type Spa.
I added a post SPA J180.
I can see Selos registered and choose which I want to display in the template.
And then they appear in the template, you can printing also using: customPostTypeTree::viewChildren($customPostTypeTree); on single.php code, or use the Array $customPostTypeTree as you wish.