How can I connect two large sets of variables with each other?

If you have two sets of variables, you can use Onyx’s node group functions to group variables together. Then you can connect the two groups with an each-to-each connection.

Select the first group of variables and click CTRL+1 (on Macs: CMD+1). This creates  group #1. Select the second group of variables and click CTRL+2 (on Macs: CMD+2). This creates group #2. Now, right-click on any node from the first group and drag a path to any variable of the second group. This will create a path from each variable of the first group to each variable of the second group.