I've made a script for Applescript editor (that all of you have) so you can run it easily so do as I say:
1. Put the files from the Simcity 4 Rush Hour.dmg in the applications folder (because my script executes on the applications folder).
2. Open Applescript Editor
3. copy this in it:
tell application 'Finder'
activate
make new Finder window to folder 'downloads' of home
end tell
tell application 'Finder'
activate
set target of Finder window 1 to folder 'SimCity_4_Rush_Hour' of folder 'Applications' of startup disk
open document file 'SimCity 4 Rush Hour.dmg' of folder 'SimCity_4_Rush_Hour' of folder 'Applications' of startup disk
delay 5
set target of Finder window 1 to folder 'SimCity 4 Deluxe' of folder 'Applications' of startup disk
open application file 'SimCity 4 Rush Hour.app' of folder 'SimCity 4 Deluxe' of folder 'Applications' of startup disk
end tell
4. test it if it works
5. if the test works, save as an application wherever you want.
Done! you can now simply make the application run by clicking the application you just made