Contact form 7 conditional dropdowns

Hi, my website is https://5spa.com.bh/contact-us-2/. I used contact form 7 to create this contact form. Where under Treatment section I need two drop-down menus. If I select one option from the first drop-down, then the second drop-down should load relevant menus. Please help me to solve this since I am not able to find a solution using contact form 7.