[Help] Multi-Reference Logic

Hi, Guys. I’m Lee from South Korea.
Nowadays, I’m trying to make Gear Rent Site for my school’s Broadcasting Service.
I made a CMS Collection which concerned with gear information like Camera Name, Categories, etc.
And I made another CMS Collection handling Gear Cart, where users can put their wished gears.
But I have some issues that I cannot submit form with Multi-Reference Data. I want to take User’s wishlist by using Multi-Reference which refence First CMS Collection about gear list.
So, Can I get submitted forms with Multi Reference? Also, Can I make Logic with Multi-Reference Data?