Can awk, sed match mult-line patterns ?

It seems to me that sed & awk are single line based ?

I want to delete blocks of text which look like:
<opening pattern>
<2 to 5 lines>
<closing pattern>

If I use the <2 to 5 lines>, I can avoid deleting all the good
stuff, up to the 'next' <closing pattern> in case the assumed
<closing pattern> is missing/undetected.

Thanks for any feedback,

== Chris Glur.