multiple aggregate_column behaviours in Propel

actual_migration.sql

ALTER TABLE `table_1` ADD
(
 `nb_something_else` INTEGER
);

expected_migration.sql

ALTER TABLE `table_1` ADD
(
 `nb_something` INTEGER,
 `nb_something_else` INTEGER
);

schema.xml

<table name="table_1">
  <behavior name="auto_add_pk" />
  <behavior name="aggregate_column">
   <parameter name="name" value="nb_something"/>
   <parameter name="foreign_table" value="table_2"/>
   <parameter name="expression" value="COUNT(id)"/>
  </behavior>
  <behavior name="aggregate_column">
   <parameter name="name" value="nb_something_else"/>
   <parameter name="foreign_table" value="table_3"/>
   <parameter name="expression" value="COUNT(id)"/>
  </behavior>
  <column name="name" type="VARCHAR" size="255" required="true" />
 </table>