Interference is a key challenge for communication systems, whether wireless for the Internet of Things or emerging approaches for the Internet of Bio-Nano Things. In the case of molecular communication between biochemical systems, interference can impact not only other communication systems, but also any nearby biological system. This leads to a different coexistence problem, where communication is constrained such that the function of the biological system is preserved. In this paper, we develop a new model for the interactions between the communication and biological systems, incorporating memory in the channel between the communication and biological systems. We then obtain an impossibility result limiting the amount of information that can be transmitted. In particular, the number of messages scales as √ n with the blocklength n.