Here is a more detailed problem description for others in case they have also seen the issue and can comment:
1. We are trying to design a portal where all variables will list as a checkbox in dropdown on the portal.
2. If user selects only 3 variable out of 5 then only selected variable would display on the screen.
3. User can input data only for selected variable on the screen.
4. If user wants he-she can add another variable as per need from Self-service portal only.