Sisters have this responsibility ahead (8)

I believe the answer is:

forwards

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'ahead' is the definition.
(I know that ahead can be written as forwards)

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for forwards that I've seen before include "Facing towards the front" , "Football players" , "In the normal sequence" , "Passes on" , "Ahead in time; in the normal order" .)

I've seen this clue in The Telegraph.

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