Smart table, how to control pop in columns on flex layout?

Hi,

Imagine I have a smart table like this:

  <smartTable:SmartTable 
    id="searchReqSmartTable" 
    demandPopin="true">

   <Table>
     <Columns>

          <Column width="40em">
            <customData>
              <core:CustomData key="p13nData"
                value='...p13nstuff'/>
            </customData>
            <Label text="Col 1" />
          </Column>
          
          <Column hAlign="End" **pop in settings**>
            <customData>
              <core:CustomData key="p13nData"
                value='... p13nstuff'/>
            </customData>
            <Label text="Col 2" />
          </Column>

          ... more columns. 
      </Columns
   <Table>
<smartTable:SmartTable

Obviously edited for brevity. My actual table has 10+ columns. I'm using this in a flexible column layout. When an entry is chosen and the list shrinks, various columns are popped in. The smart table seems to override any pop in settings on the column definition and do it's own thing with the column settings. How can I hide certain columns on phone/table layout sizes?

What I'm trying to accomplish is that the full screen list on the flex layout has 10 columns, but displays only 2 columns when displaying the middle section of the flex layout.