In this paper we propose a three-way partitioned resource reservation approach to deal with congestion in heterogeneous cellular networks as a result of densely populated mixed traffic scenarios analogous with the Fifth Generation (5G) networks which will host Factories-of-the-Future (FoF) environments. Our approach lends to the reduction in random access delay budget through a combined static/dynamic resource usage approach with respect to traffic types with different latency requirements. In addition, we obtain figures for optimum performance random access (RA) resource partitioning for ultra Reliable Low Latency (uRLLC) and non-uRLLC traffic.