Adjust space between two section

Hi Everyone,

I am  designing PDF form for customer and form is divided into 3 section and each section has 10 rows and that rows will be hidden and rows will be appar as information entered into them. if user fill out 3 rows than 3 will be appear and 7 will be hidden and that many space looks extra space. so, how can I adjust the space between two section? 

please help me!

thank you in advance!