Always open a file in a specific program
Solution 1:
If you don't mind specifying InDesign 5.5 every time, then this command line should work:
open -a 'InDesign 5.5' myfile.indd
If you're going to do this often, you can wrap it in a shell script or bash function like
function indd() { open -a 'InDesign 5.5' "$@" ; }
Then you'll be able to simply say
indd myfile.indd