[NEST Users] Connection management for huge network

Dear all, In my working group, we are working on the creation of the spiking neural network of human CA1 (4.8 million neurons). We are using a specific function for defining the connection between the neurons. This function gives us 30 billion pairwise connections. We would like to know what the most efficient for the creating the network in NEST 3 using this pairwise connectivity. Thank you in advance for your answer, Kusch Lionel