What you could do is to have your teasers as pages and link to with a LinkCollection .
Or you could when you create a section also create a corrosonding keyword, and tag the teasers with one or more keywords. (sorting is a problem then)
Thank you Anders!
I will try to use LinkCollection.
My business task is: there are "sections" and there are "teasers" in it. System should enable users to add new "sections" and attach "teasers" to it. As I undersatnd it can be done, if I create "sections" like pages, and attach "teasers" to each page as property. I know, that it is possible to create property as collection of items: http://labs.episerver.com/en/Blogs/Anders-Hattestad/Dates/2008/10/Properties-in-CMS-5/ .
The problem is: requirements say, that each "section" may contain many "teasers",and each teaser can be included in many "sections".
I have some thoughts about hot to implement it (create "teasers" not like properties, but like pages, and create LinkCollection property it each section to refer "teasers"), but probably there is some standard solution of such task?