add value to multiselect dropdown or dropdown using Rule

Hi,

I am using K2 for SharePoint and I have a scenario like  I had a list with multiple items I need to read each item and have to append value from particular column into a multi-select drop down.

Eg

++++

List A

++++

Column 1     Column2

```````````````````````````````````````````

Item1                  abc

Item2                  sdf

Item 3                 ert

have to append column2 values into drop down.

like this when Dropdown is clicked it should show this values in dropdown(first value-->abc,2nd value-->,sdf,3rd value-->ert)

Thanks in advance...