The solution is to write the different links on different lines. Like this:
[symlinks]
recipe = cns.recipe.symlink
symlink =
targetname1 = linkname1
targetname2 = linkname2
You can add as many links as you like by putting each one on a new line.
You can read more about it in the source code for the recipe here. The documentation on that page above is unfortunately rather poor though.