In my project, we are working on 7.1.9 version and we have a business requirement to have tabbed Portal central work area. And inside any tab of this tabbed Portal central work area, there can be a series of tabs inside it, when we click on links within that tab. I have tried to draw a sketch of the requirement below. If somebody can suggest a possible solution, it willbe great.
As per your project requirement, I find you could use Layout Groups and use layout group format as 'Tab'
Layout group as the name implies groups several layouts and presents them together. A Layout group can contain any number of Dynamic layouts, Column layouts, repeating Dynamic layouts, or other layout groups. The Layout group allows you to specify the type of navigation a user will use to navigate sets of information. Refer Pega Academy >> UI Specialist (7.1) >> Using Layout Groups.