.mak file for directory with source code in subdirectories

Hello group,

I have a set of directories, each with sub folders that contain source
code. For each of these I am trying to write a .mak file, and then have
each build from this and pull the resultant libs together at the end to
form a binary.

So, I have my list of sources ...

SRCS = \
  example/file.cpp
  different/example/file.cpp

I then have the following ...

OBJS := $(patsubst %.cpp, $(BLD)/%.o, $(SRCS))

$(BLD)/$(TRG) : $(OBJS)
	@$(DBG_AR)
	@$(AR) $(ARFLAGS) $(OBJS) $(ARFLAGS) -o $@

In the example I copied this from, the files were all in the same
subdirectory, and the author had used this trick ...

vpath %.cpp code/directory

Obviously I can't use this trick, and it chokes for me, I think that is
because of the directories difference.

Can anyone advise me on what to do here?

Cheers,

Gaz