|On a single system, you register your program as the handler for file2's type, or hook into the handler in some way. Examine the file in question. If it's file2, you do your special handling (launching file1.exe). If not, you do the normal handling. |
Across multiple systems, it's an impossibility. It has to be. Otherwise, I could run a "wipe drive" program on anyone who stumbles across this page.
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