Google Data Studio Custom dimension showing incorrect data

I was trying to create a custom dimension that will take specific pages together for my GDS report. I need to create a dimension out of 4 pages to calculate metrics for them. Here's what I was trying to do/have tried:

CASE
WHEN Page = "www.link1" 
OR  Page = "www.link2"
OR  Page = "www.link3"
OR Page = "www.link4"
THEN 1
ELSE 0
END

I've also tried using IN

CASE
WHEN Page IN ("www.link1","www.link2","www.link3","www.link4")
THEN 1
ELSE 0
END

My formula gets accepted but it shows the wrong data. My ultimate goal is to draw a time-series chart of date vs the sum of pageviews for the particular custom dimension of these 4 pages. I am totally clueless about where I am going wrong.

Summary

One way it can be achieved is by applying a Filter to a Time Series chart:

1) Time Series Chart

• Date Range Dimension: Date
• Dimension: Date
• Metric: Pageviews

2) Filter

Include Page In www.link1,www.link2,www.link3,www.link4

Google Data Studio Report and a GIF to elaborate: