Data entry over multiple sheets

I have a database of students in CC CONTACT and I want to put them into lesson groups on CC Monday. Since I have a significant number of students to plug into lesson groups, it would be a pain to plug each student individually by copying and pasting. What I have figured out to do is setup a drop down list in CC MONDAY under each GROUP through data validation to have access to my database in CC CONTACT to plug a students name in from that database. Being the nerd that I am, I'm not satisfied with that. Therefore, I want a formula (and I KNOW it's out there) that will allow me assign students to a group (GROUP A, GROUP B, GROUP C, etc...) in the GROUP field of CC CONTACT and have those changes reflected in CC MONDAY. So student x,y&z that are assigned to group "A" in CC CONTACT will be automatically plugged into to GROUP A of CC MONDAY. I would like a formula to transfer or lookup data instead of manually entering each name. Or vise versa.