Merge two exe files into one programmatically

Question

Is there a way to merge two exe files into one, programmatically, so that running it would execute both older exe files together. I found some things on google about injecting code or dll files but is it possible two merge two exe files or to inject exe into exe?

Thanks in advance.

[EDIT] Thanks everyone. Just for those who said that it's not possible, I have to say I almost did it in the end in the way some suggested. It almost goes like this (I can't remember all of it cos it was a long time ago):

[BEWARE: This algorithm is very similar to those of some worms and viruses. I am not a hacker or a virus writer! and this is to be used only for experimental or unharmful reasons - Making mistakes in the code can ruin the executables in directories.]

1- The Exe checks itself's size to detect whether anything has been appended to itself. if it hasn't then:

     1.1- The exe finds other executable files in its directory (lets call one of them as victim!)
     1.2- it makes a copy of itself (lets call it newMe)
     1.3- it copies the other executable found in the directory to the end of newMe.
     1.4- it deletes the other executable file found and renames newMe to its victim's name.

2- If the exe detects that something has been added to it then:

     2.1- Then it copies data from itself (from ORIGINAL_FILE_SIZE to the end of file) to a new file (lets call it newBorn.exe)
     2.2- It runs itself's code and then executes the newBorn.

I said I ALMOST did it cos in this way the exe appends another exe to itself. but this could be repeated for appending and executing 2 or even 3 or more executables into one. you just have to know the ORIGINAL_FILE_SIZE of the written program.

Answer 1

Theoretically this is possible, but it will take some effort from your side.

You can append data to an exe file, this is how self extracting archives work. However, you'll need your own data format, similar to a file system, because you've got just one flat .exe file.
See this Microsoft article (there's a lot more on google) http://support.microsoft.com/?scid=kb%3Ben-us%3B84062&x=12&y=13

The exe you're packing your two files in must then extract those files and can finally run them.

Good luck.