How to make list collector variable dependent based on the selection from select box variable?

Hi all,

I got a catalog Item where I run data lookup policy. (from a customized table)

I do populate a list collector variable with relevant values at once based on the selection from a select box variables. 

It works fine but user asked me not to populate values at once. User wants to select multiple values manually.

I am attaching the screenshot to show the current behaviour. How can I stop values being populated at once?

Subdivision list collector values do get populated automatically based on the selections of functional line and division selections via data lookup policy. I do want values not to be populated automatically but selectable by user manually.