Makefile object lists and object locations

I have my object files compiled into a specific location using these variables and targets:

OBJDIR=./obj

objdir:
    $(MKDIR) $(OBJDIR)

%.o: %.cpp objdir
    $(CXX) $(CXXFLAGS) -c $< -o $(OBJDIR)/$@

Now my problem is, when it comes to linking the executable, I want to use variables to hold the lists of object files, such as:

FOOOBJECTS=foo.o foo1.o foo2.o
BAROBJECTS=bar.o bar1.o

mycrappyprogram: main.o $(FOOBOJECTS) $(BARBOJECTS)
    $(CXX) $(FOOBJECTS) $(BAROBJECTS) -o $(BINDIR)/mycrappyprogram

Of course I can't do this because all the objects are in ./obj/ so the recipe can't find them.

How can I define a list of object files once, and have them be qualified when used in the recipe?