Multitrack files in separate tracks

is there a way to layering a multitrack file on separate tracks on the editor?
I’m actually importing a 4track file and I would like to treat each of them separately.
Is there’s some setting I have to setup?

In the import dialog there is an option at the bottom called “Mapping” that can be set to “1 track per channel”.

Ok, thanks.
It means split the file during the importing.
What about a session that already has multitrack files on it?
Is there any chance to choose which file I would like to move on separate tracks and keep the others on multichannel tracks?