Sorry, I read examples for attributes. The process setup is basically the same, the trick is to transpose the example sets, such that rows and columns are interchanged. Then you can do the same as in the process before and then transpose back, et voilą!
Hope this helps

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.2.002">
<context>
<input/>
<output/>
<macros/>
</context>
<operator activated="true" class="process" compatibility="5.2.002" expanded="true" name="Process">
<process expanded="true" height="386" width="1150">
<operator activated="true" class="generate_data" compatibility="5.2.002" expanded="true" height="60" name="Generate Data" width="90" x="45" y="30">
<parameter key="target_function" value="random classification"/>
</operator>
<operator activated="true" class="aggregate" compatibility="5.2.002" expanded="true" height="76" name="Aggregate" width="90" x="179" y="30">
<parameter key="use_default_aggregation" value="true"/>
<parameter key="default_aggregation_function" value="sum"/>
<list key="aggregation_attributes"/>
</operator>
<operator activated="true" class="transpose" compatibility="5.2.002" expanded="true" height="76" name="Transpose (3)" width="90" x="380" y="165"/>
<operator activated="true" class="transpose" compatibility="5.2.002" expanded="true" height="76" name="Transpose" width="90" x="380" y="30"/>
<operator activated="true" class="filter_examples" compatibility="5.2.002" expanded="true" height="76" name="Filter Examples" width="90" x="514" y="30">
<parameter key="condition_class" value="attribute_value_filter"/>
<parameter key="parameter_string" value="att_1 > 5"/>
</operator>
<operator activated="true" class="select_attributes" compatibility="5.2.002" expanded="true" height="76" name="Select Attributes (2)" width="90" x="648" y="30">
<parameter key="invert_selection" value="true"/>
</operator>
<operator activated="true" class="replace" compatibility="5.2.002" expanded="true" height="76" name="Replace" width="90" x="782" y="30">
<parameter key="attribute_filter_type" value="single"/>
<parameter key="attribute" value="id"/>
<parameter key="include_special_attributes" value="true"/>
<parameter key="replace_what" value="sum\((.*)\)"/>
<parameter key="replace_by" value="$1"/>
</operator>
<operator activated="true" class="join" compatibility="5.2.002" expanded="true" height="76" name="Join" width="90" x="782" y="165">
<parameter key="join_type" value="left"/>
<list key="key_attributes"/>
</operator>
<operator activated="true" class="transpose" compatibility="5.2.002" expanded="true" height="76" name="Transpose (2)" width="90" x="916" y="30"/>
<connect from_op="Generate Data" from_port="output" to_op="Aggregate" to_port="example set input"/>
<connect from_op="Aggregate" from_port="example set output" to_op="Transpose" to_port="example set input"/>
<connect from_op="Aggregate" from_port="original" to_op="Transpose (3)" to_port="example set input"/>
<connect from_op="Transpose (3)" from_port="example set output" to_op="Join" to_port="right"/>
<connect from_op="Transpose" from_port="example set output" to_op="Filter Examples" to_port="example set input"/>
<connect from_op="Filter Examples" from_port="example set output" to_op="Select Attributes (2)" to_port="example set input"/>
<connect from_op="Select Attributes (2)" from_port="example set output" to_op="Replace" to_port="example set input"/>
<connect from_op="Replace" from_port="example set output" to_op="Join" to_port="left"/>
<connect from_op="Join" from_port="join" to_op="Transpose (2)" to_port="example set input"/>
<connect from_op="Transpose (2)" from_port="example set output" to_port="result 1"/>
<portSpacing port="source_input 1" spacing="0"/>
<portSpacing port="sink_result 1" spacing="0"/>
<portSpacing port="sink_result 2" spacing="0"/>
</process>
</operator>
</process>