A specific encrypted dual-boot setup

I would like to install Manjaro alongside another Linux distribution (let’s say Arch). I want a “data”-partition shared between both installations, and I want my whole system (excluding the boot partition perhaps) to be LUKS encrypted. Can you describe what I need to do in order to set this up? I don’t care if the Arch Linux partitinon is decrypted when I boot into Manjaro, or not (and vice versa). Can I do the Manjaro part with the graphical installer?