2 Visit visa applications- duplicates of documents

[ratapita]

Hello helpful people,

I am applying for a visitor visa for my parents. Obviously I would be submitting original of documents like, Salary slips and Bank statements , but you only get one set of originals . So for the 2 applications;
Do I to submit the originals with one application and provide
-photocopies
or -certified copies
or- just made a mention that in the cover letter that the other application has the relevant originals ?


Many thanks in advance.

Ratapita