I don't subscribe to digital mags so am not sure what format they are saved in.
IF they are .pdf files and if you are using a PC (not Mac or tablet or Kindle etc) you can purchase a program called Cute PDF Professional online. It lets you extract and save selected pages from .pdf files and save them separately. Costs about $30.00 or so. Use it at work and is well worth the price. Just Google it and take alook.