awk or sed or grep filter a line and/or between strings

Hi, I have multiple files on a directory with the following content:

blahblah
blahblah
hostname server1
blahblah
blahblah
---BEGIN---
aaa
bbb
ccc
ddd
---END---
blahblah
blahblah
blahblah

I would like to filter all the files with awk or sed or something else so I can get below output

hostname server1
---BEGIN---
aaa
bbb
ccc
ddd
---END---

I can do awk '/---BEGIN---/,/---END---/' * but I don't get the hostname server1 line.
I have hundreds of file so the 'hostname server1' would at least give me some idea from which file is the output coming from.
Ideally I would get

hostname server1
---BEGIN---
...
---END---
hostname server2
---BEGIN---
...
---END---
...

Any suggestion on how can I achieve this?

One way:

awk '/---BEGIN---/,/---END---/ {
  if ( !F[FILENAME]++ ) print H " " FILENAME
  print $0
}' H=${HOSTNAME:-$(hostname)} *

I received a PM that my post is not clear, I'm sorry about that so I would like to update my post as below.

I mentioned that I have hundreds files, probably let's just start with one file.

I have a file, filename is config.txt and below is the content

I would like to filter using awk or sed and get something like below

Your post seemed perfectly clear to me, even thought I misread it! It seems you want just the hostname, not the filename.

awk '/---BEGIN---/,/---END---/ {
  if ( !F[H]++ ) print "hostname " H
  print $0
}' H=${HOSTNAME:-$(hostname)} file*

If you're pulling these files from multiple hosts, you might want to add the hostname to the filename or in the file itself.

Yep, the 'hostname' has same value as the 'filename' in my case so that does not really matter I think.

I'm still learning Linux ans I was expecting a one liner command. Apparently I need to learn more about script/bash scripting based on your reply.
I'll do more reading and practicing on awk and bash script.
Thanks Scott!

If I understand your post correctly, you might want to try:

awk '/^hostname /;/---BEGIN---/,/---END---/' file*

That works perfectly! Thanks Don Cragun