Question about passenger-list order

Hi, I have a (somewhat stupid) question about passenger lists: Are passengers who are written on ledgers organized by the order of who's "in line'? Sorry for my ignorance... Bjørn Trulsen Ruud and his brother Truls travelled with his sisters Anne and Ingrid but they're not on the list "together" but in two separate areas. Bjorn and Truls' names Anne and Ingrid's names Oh and I know there's no solid way to find out- but I thought it curious before Truls and Bjørn's names there are two young women the same age. Travelling together? Thanks for any and all answers--- this website has saved me... hahaha[:I]