The hostages are a group that’s assumed to be complete. That’s like if someone stole your tires off your car and offered to give “your tires” back to you but only 2 of the 4. People assume they offered all the tires if the headline doesn’t say otherwise.
If you include the partial hostage release, it essentially robs the story as it’s clear why you wouldn’t do a deal for some of the hostages. Making any deal for some of the hostages is stupid.