partial linking

I have source tree with many folders containing many .o files each. I 
wish to partially link the contents of each folder so I have one 
combined .o file (library?) for each folder. These combined (object 
files?, libraries?) will go thru a final link step at a later stage in 
the build.

Is there anything special about how this partial linking or can I just 
do something like:

$(OBJS)=a.o b.o c.o
mylink.b : $(OBJS)
	ld -o mylink.b $(OBJS)

Does building in this multi-tiered fashion result in a larger final 
image, or can the final link still remove redundancies?