For private sessions you'll need to start from story mode first since that's the only way to properly set this up. Once there open the pause menu and look for the online tab, then play gta online where you'll find invite only session this keeps everything locked down tight. Watch the timing here because if you try jumping straight to online from startup it won't give you the private session option. After you're in, hitting the friends menu lets you send invites out to your trading partners.

Here's something interesting while private lobbies are definitely safer for moving product around, selling in public ones gives you that sweet 50% bonus payout (assuming it's a full lobby). If you're going the private route though, stick to using the terrorbyte for remote sales management, and definitely grab ghost organization when you need it. Position yourself away from the city center, especially during sales runs since that's where most trouble starts. The nightshark or insurgent are solid picks for transport, just remember to keep your distance from any sketchy areas where players tend to cluster.

Good to know the invite system works exactly the same whether you're on pc, playstation or xbox so no need to worry about platform differences when setting everything up just make sure everyone's properly invited before starting any big sales.