I am a contributing author over at MixingLight.com, a colorist's subscription website. Where remote work and moving tons of files is a daioy discussion on their Slack.
There's all sorts of ways, different software and software/hardware options, so many I can't keep track of all the ones they talk about. A comon one for editing that I've heard of for similar situations is distributing low-res proxies of the b-roll. When the editiors actually use it, and it's accepted ... then they get the original full-res file from the central supply. That way only a small amount of media is sent to everyone.