sorry for the confusion please allow me to be clear.

Hilton honor account is under Tom.

Tom recently opened up amex card and got sign up bonus
Susan wants to open up same card and get sign up bonus but she wants to transfer those sign up bonus points to Tom's hilton account. so when she is asked put hilton honor account when applying for amex hilton can she put Tom's hilton account number?

and there might be 2 other people who wants to open Amex hilton and transfer sign up bonus points to Tom's hilton account.

hope this clears a bit.