text functions in implicit rules

[Jan Althaus]

Ahoy!

is it at all possible to create an implicit rule that'd do something  
similar to:
%.o: $(subst foo,bar,%.cpp)

The reason I'm asking is that I'd like to have a makefile that takes  
a list of source files that are potentially scattered over different  
directories, but builds the objects/dependency files into a single,  
common dir.
The idea would've been to mangle the names so e.g. ../foo/bar.cpp  
would become address@hidden@bar.o

Am I fundamentally asking the wrong question? Is there a way of doing  
this without scattering the objects/dependencies over the sources  
dirs? (in a way that allows the list to contain absolute paths and  
the like?)
Ta!

Jan