Spring incremental configuration using PropertyPlaceholderConfigurer

Question

I'm trying to find a way to re-use a spring configuration. The component I want to reuse is working like that:

The component is assembled inside the Spring context using a 'configBuilder'. The config builder is a bean that parse a string retrieved from a PropertyPlaceholderConfigurer to create a Config bean. The resulting config bean is injected into the component.

here is sample config file:

<bean id="propertiesPlaceholder" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <util:list>
                <value>classpath:myService.properties</value>
            </util:list>
        </property>
        <property name="ignoreUnresolvablePlaceholders" value="true"/>
    </bean>

    <bean id="myServiceConfigBuilder" class="com.ServiceConfigBuilder"/>

    <bean id="myService" class="myServiceConfigBuilder">        
        <property name="serviceConfig">
            <bean factory-bean="myServiceConfigBuilder" factory-method="buildFromProperty">
                <constructor-arg value="${config.parameters}"/>
            </bean>
        </property>
    </bean>

The service is a Spring post-processor that applies on some properties of some beans. Selecting properties is done using the config builder using expresions like:

beanA: property1, property2

So I want to be able to add more expression while loading my root context and its children.

For example if I have: rootContext that imports (kidA, kidB, kidC), I want to able to declare the post processor service in rootContext, read a first property from rootContext to create a config, and then to read a property for each sub context and create config from each of them. The postprocessor will be then created using a merged config.

Do you see a way to achieve this ? The PropertyPlaceholderConfigurer is not looking like a good solution, but I don't have any idea of how to perform that.