I would love to know this too.

I also thought, OK, maybe I can create a static group populated "with a search" but again you have to re-enter the criteria rather than being able to choose an existing search. Next I thought, I could try using a dynamic group as a criteria in search to populate the static group. NO luck, same problem one level up.

So can dynamic groups only be used in marketing?

My goal is to update customers in a mass update based on their membership of a dynamic group built on a postcode search. I don't want to have to rebuild/duplicate the many lines of the postcode search in the mass update criteria (already miffed we have to do that for sales territories).

We should be able to specify dynamic groups as a filter, or use an existing saved search to populate the mass update criteria.

The only way I can think of to avoid repeatedly entering search criteria in multiple places (regular saved search, sales territories, mass update criteria) is to have some sort of suitescript that could periodically take the results of a dynamic group and copy that over a static group that you could use in the group criteria of those other searches.

Just trying to avoid duplicating work (and then maintaining those multiple places that criteria is entered everytime there's a change) when you have 100 postcodes in a search criteria.