Hello Lélek,
It depends on the Booking.com settings, as in case they include properties blocks to their external links, then they will be imported to the Hotel Booking calendars. If blocks are not included in export links, there is no way to have them imported to the Hotel Booking.
You may open any Booking.com export link in the browser and open the .ics file to find out whether added blocks at Booking.com are included in a link. For example, there is an option in Hotel Booking plugin to export or to not export accommodation blocks, perhaps there is similar setting at the Booking.com somewhere.
Regards,
Andre