Repeating Repeatability Symbol

Communication Error:

ld: duplicate symbol _OBJC_METACLASS_$_Reachability in /Users/jmf/Documents/iOS Development/jmf_Client/jmf/jmf/ww_libs/libmfcbroem_ios.a(Reachability.o) and /Users/tpf/Library/Developer/Xcode/DerivedData/jmf-erlknghfcpoomnfanzovahfacgpv/Build/Intermediates/jmf.build/Debug-iphoneos/jmf.build/Objects-normal/armv7/Reachability.o for architecture armv7

If I just delete the h / m files (and the corresponding import directives) in the hope of only using Reachability in libmfcbroem_ios.a ... the linker throws this out:

Undefined symbols for architecture armv7:
  "_kReachabilityChangedNotification", referenced from:
      -[MKNetworkEngine initWithHostName:customHeaderFields:] in MKNetworkEngine.o
      -[MKNetworkEngine dealloc] in MKNetworkEngine.o
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)

How can I tell the linker to use Reachability from file "a"?

(disclaimer, I'm just starting with ObjC / iOS)

Thanks for any help ...