Problem:
Create new posts in different post types which are connected with front end form

Solution:
If you have post type A and post type B and you want to submit the post for both post type A and post type B from frontend, you will require one form for post type A to submit entries related to post type A and another form to submit entries for post type B. That means you will require two forms.

You can find the proposed solution in this case with the following reply:
https://toolset.com/forums/topic/create-new-posts-in-different-post-types-which-are-connected-with-front-end-form/#post-2296729

Relevant Documentation:
- https://toolset.com/course-lesson/front-end-forms-for-adding-content/