Issue in ISOWEEK in IDT

Hi All

I have requirement that I should display past 6 weeks of
data from the User Week input (Prompt)

We are using SAP HANA as a backend and I am not able to do
Minus on ISOWEEK in IDT Universe(SAP BO 4.1).

    I would like to acheive below thing

WEEK

BETWEEN

USER ENTERED WEEK

AND

(USER ENTERED WEEK)-6

Pleasse let me know how to acheive this

Thanks

Ajith