The Apple GUI method is clean and neat for most folks to use, and the enclosing Archive folder prevents the inadvertent overwriting of files. In your case, you'll have to use the command line in Terminal to do what you want using the commands zip and unzip.
Read the man pages for zip and unzip for a fuller appreciation of what is possible.
Step 1: zip up the files
• Run Terminal
• execute: zip /path/out_filename /path/in_filename
You can select multiple files (from different directories & disks, too) and drag from the Finder GUI into the Terminal window. Terminal will expand /path/ for you in this case.
Ex: zip ~/Desktop/all_zipped_up ~/Desktop/zip_me_up.txt ~/Documents/zip_me_up2.txt
This creates all_zipped_up.zip to the Desktop in this example.
Step 2: unzip the files
The key to unzipping without creating an enclosing folder is to use the -j switch:
• Run Terminal
• execute: unzip -j /path/out_filename
• The expanded file(s) will appear at the same path as the source .zip file. You can also use the -d switch to expand into another path. According to the man page, the -d switch can go almost anywhere in the command line. I put it at the end because it is a logical place to put it.
Example to expand to same path as the original archive:
unzip -j ~/Desktop/all_zipped_up.zip
Example to expand to alternate path:
unzip -j ~/Desktop/all_zipped_up.zip -d ~/Desktop/New_Folder