I don't know of any standard trick that would do this -- the general conception of problems is that they are separate and self-contained. Someone else might have a clever idea that would work.
This isn't clever, but I often use the homework set 0 (setHeaderXX.pg) file for purposes such as this. I use it to give either a description of the purpose of the problem set, or external references that might be useful. It could be used to give a general outline as well.
Referring back to this set would still have to be done manually as far as I can see.
Hope this helps.