What is Partial Crossbar Interconnection
As I interpret your diagram you can connect each group of 4 input/outputs to the I/O pin group [1..4] of your choice. That is a crossbar. But in FPGA1 you can't choose to which I/O pin within the group your A connects: the connections within the group are fixed A->1a B->1b C->1c, D->1d. 

In FGGA2 you can (probably) switch the lines within a group, but you can't switch between groups.

The total effect is that you can


in the first level crossbar direct a group of 4 in/ouputs to a group of I/O pins
in the second-level crossbar direct a pin within a group to aqnother pin within that group