Programming :: Adding External Module To Kernel Source?

There is a module A which is compiled with the kernel. I wrote an external module B which exported a symbol using EXPORT_SYMBOL.The module A now needs to talk with that exported symbol (function call). For that i modified A so that it includes the function call from B. However i now get unidentified symbol errors during 'make' operation as symbols of B are not present during kernel compile and A now kind of depends on B.

One solution is that make B part of the kernel as well. However, it would mean that whenever now i try to compile a kernel with a different source, i have to modify the config files and everything to accommodate B.Hence i am seeking a solution which does not include modifying the kernel.