How to get only specific text rotated within a text box?

https://community.adobe.com/t5/indesign-discussions/angular-text-inside-textframe/m-p/15085134#M605366

now it's two seperate text  boxes (or rather 3)

how can I get it all in one with just the highlighted text rotated?

Can you post some screenshots? 

Because it can range from individual letters to the whole block of text. 

But if you're asking if you can rotate multiline paragraph, by let's say 15 degree - you would've to move it into a new TextFrame, rotate it - or its contents - then Anchor / InLine this new TextFrame in the original text.