No, you cannot. Scribus' Text Filter does not feature regex (regular expressions) like frame break, line break, non-breaking spaces etc.
But I found a (dirty, probably not always working) way to get to a similar result in Scribus 1.5.0 or later.
- In your source file add the following line whereever you want a frame break:
/###############################################screwscribus
- In Scribus, create a new Paragraph Style, give it a recognizable name (e.g.'framebreak') and apply the following settings:
Font Size: 1pt
Fill Color: None
Stroke Color: None
Background Color: None
Space Below: 300pt
- Make sure, that all paragraph that should go on one page together, have their 'Keep together with next paragraph' an 'Do not split paragraph' box checked within the Style Manager:

- When importing text and using the text filter, apply your Paragraph Style from point 1 to all paragraphs starting with '/###############################################'

There is no guarantee that this will work but if everything goes well, Scribus will now try to keep all paragraphs together, that we want to go in one frame and then jump to the next frame.