It sounds like you are just looking for a layout component. Which you can achieve like so:
Add a body to your layout component (parent)
<container xmlns:t="http://tapestry.apache.org/schema/tapestry_5_3.xsd" xmlns:p="tapestry:parameter" t:content="text/html; charset=utf-8">
this is parent component<br/>
<t:body/>
</container>
Since you'll control the content form the "child" component, you don't need to pass in the variables.
public class ParentComponent {
}
Control the content of your layout component (parent) from within the child component.
<t:ParentComponent xmlns:t="http://tapestry.apache.org/schema/tapestry_5_3.xsd" xmlns:p="tapestry:parameter" t:content="text/html; charset=utf-8">
body of c1 1, 2, 3
</t:ParentComponent>