make static pattern rule

[YourName]

I want to transform files form fileName (ie no extension) to fileName.pp 
using my utility "xform".
Using make (3.80) static pattern rule:

files = fileA.pp fileB.pp
$(files): %.pp: %
        xform $< > $@


only the first file (fileA.pp) ever gets processed (ie created).
When a non matching file name (fileC) is appended to the 'files' list a 
warning is issued, so i concluded target fileB.pp would be processed 
somewhere along the way although it most definitely does not exist. What am 
i missing here?