How to change block content on a page via code

Not sure if this is possible, but if someone has the skills and knowledge ... I would appreciate the information.

I normally use this widget for setting up php content in pages

My idea would be to create a page with 2 blocks. 1 block would display 3 buttons and the other block would be empty (waiting for a code line)

When the user clicks in one of the buttons, the button instruction should add a "iframe" line in the empty block so it loads the content from an external source.

Not sure if I made myself clear, but the idea is to be able to change a block content on the fly using another block to send the code lines