auto-populate table from data from another table?

I have created a database,

Pupils, Class, Registered Class Pupils, Session Occurence.

1 Pupil can take many classes (via the registered class pupil table).

A session takes place every week for the pupils registered in a class, and I want to record their attendance (i.e attended yes/no) but I want their names auto-populated from the registered class pupil table, so I don't need to select each pupil name time and time again.  

Any ideas of how I can acheive this please?

Thanks in advance.