You’ve already asked and got detailed replies in this in two earlier posts. In short, UE4 scenes doesn’t support rendering different perspectives at the same time.

Before repeatedly asking the same question, please take the time to read the replies: https://my.aximmetry.com/post/597-preview-before-broadcast

I don’t understand? How is this different from the previous two posts? 

In any case, the answers you got in the previous post that I linked to still applies to this question.

https://www.youtube.com/watch?v=aQMIaZZE26I&t=2s