Can both my parents have the interview on the same day despite having individual NVC?

[shanoza]

I filled out DS-260 for my father in September and for my mother three months later (by mistake). In addition, NVC issued each parent a separate NVC case number.
Will they be able to have the immigrant visa interview on the same day?

Side note: I followed the instructions and filled out I-864 for each parent separately. NVC issued a case number for each parent. Now I am worried that because of two different case numbers and filling out DS-260 form four months apart for each parent, they will not be scheduled for an interview on the same date. Please help!
Thank you in advance!