How to set up Nutch to only crawl links on designated web pages repeatedly?

[Jun Zhang]

Hello,
I want to only crawl links on several designated web pages (for example A, B, 
and C). The links (for example A1, A2, A3, B1, B2, B3, andC1) on the pages 
might be deleted or added. How to only crawl these links on these pages, but 
not include other links on other pages (for example the links on page A1, A2, 
A3, B1, B2, B3, and C1)?
I appricate any suggestions or help very much. 
Thank you.Junqiang