how to undefine targets?

[Christopher Bottaro]

hello,
i have a bunch of targets defined in a file thats "included" in a lot 
of my projects.  some projects need to use just a few targets from the 
included file, but then override some of the other targets.  is this 
possible?  as of now, i do something like this:

include /path/to/my/file

# override the install target
install: blah
        blah blah

but its inconsistent.  sometimes it gets overwritten, sometimes it 
doesn't.  is there a "right" way to do this?

thanks.