Wrap A Page?

is there a way to "wrap" an external page within the site? Like an iframe would?

I want to show a page from another site within my site...

Try to create new CMS page, switch WYSIWYG editor to the source code mode and insert iframe there

It does not seem to "switch" from one mode to the other, rather there is a popup to enter the source code. I enter the code but it does not work.

I also created the page and pasted the code (instead of an iframe), but cscart seems to strip the code out. is there a way to prevent it from doing that?

I have just tested it on the demo

Admin panel: