Developing e cient performance evaluation methods is important to design and control complex production systems e↵ectively. We present an approximation method (SLQNA) to predict the performance measures of queueing networks composed of multi-server stations operating under di↵erent service disciplines with correlated interarrival and service times with merge, split, and batching blocks separated with infinite capacity bu↵ers. SLQNA yields the mean, coe cient of variation, and first-lag autocorrelation of the inter-departure times and the distribution of the time spent in the block, referred as the cycle time at each block. The method generates the training data by simulating di↵erent blocks for di↵erent parameters and uses Gaussian Process Regression to predict the inter-departure time and the cycle time distribution characteristics of each block in isolation. The predictions obtained for one block are fed into the next block in the network. The cycle time distributions of the blocks are used to approximate the distribution of the total time spent in the network (total cycle time). This approach eliminates the need to generate new data and train new models for each given network. We present SLQNA as a versatile, accurate, and e cient method to evaluate the cycle time distribution and other performance measures in queueing networks.