Feature to be installed depending upon user selection using checkbox in wix installer

I have created the dialog in wix which has 3 checkbox. user can select either one or all at a time. depending upon the selection of check box the feature needs to be selected and installed.

Suppose I have 3 application (ABC, DEF, GHI) and these are defined in the feature with condition statement.

<Control Id="ABC" Type="CheckBox" X="190" Y="110" Width="50" Height="17" Property="PQR" CheckBoxValue="1" Text="ABC">

similarly for other 2 application also I have the checkbox control.

Now I have 3 features like below.

<Feature Id="abc" Title="ABC" Level="0">
  <Condition Level="1"><![CDATA[PQR="1"]]></Condition>
  <ComponentRef Id="InstallABC"/>
</Feature>

I don't want to add the PQR as property in product.wxs because I don' want the checkbox to be selected by default.

Is it possible to do it using custom action.

Any answer or suggestions will be grateful.