Have you tried dropping your section into a harness and using the 'display' action for the mashup?

Yeah it does work with a harness. Actually i have many sections to be displayed. Just wanted to avoid creating a harness for each section to be displayed.

How about configuring Harness with Tabbed layout, each tab will have one section. Conditionally display each tab based on mash up display. 

Pega Web Mashup enables you to embed an application in a web application and allows our web application to communicate with the Pega 7 Platform.

Steps to follow

1. In the navigation panel of App Studio, click Interfaces.
2. In the Create new channel interface section, click Mashup.

  3. In the Name field, Enter MyknowPegaUI Blog as the name for the Mashup channel interface.

4. Define the Pega PlatformTM instance. For this task, use the default value in the URL field.

5.To generate the mashup snippet with URL encryption that protects sensitive data, leave the Use encryption toggle turned on.

6. In the Configuration section, define the action that is performed by the mashup code:

1. In the Action field, use the default Create a new case option.
2. In the Case type field, selected PegaUI Blog from the list.
3. In the Skin field, selected HRApp from the list.
4.  
5. Accept the default values for the remaining options.
6.  
7. Click Save.

Click on the Generate mashup code button to get the IFrame and Mashup code

Result:

Your mashup is ready to be embedded in a host website.

Previewing the mashup

After you configure your mashup, use the preview function to see how it is displayed on a page.

1. In the App Studio header, click Back to preview.
2. In the App Studio header, next to the name of your application, expand the interfaces list, and then clicked on MyknowpegaUI Blog.
3. In the Preview mode field, select Live website from the list.
4. In the Website URL field, enter https://design.pega.com/
5. Turn on the Load in a popup toggle and click Apply.

6. In the pop-up window, click the page to display wireframes, select a place, and click to insert your mashup.

Click anywhere on the page to insert required mashup

Note: By using the options in the toolbar, change skins and sizing to see how the mashup display adjusts.

For moreInformation please refer below links

https://community.pega.com/knowledgebase/articles/pega-web-mashup/tutorial-creating-mashup-pega-web-mashup

https://community.pega.com/knowledgebase/capabilities/mobility/mashup-sdk/web-mashup

https://community.pega.com/knowledgebase/articles/pega-web-mashup/pega-web-mashup