Topband: RX splitter - ground common or not?

[Zivney, Terry]

DX Engineering/s RSC-2 splitter appears to have all three antenna terminals connected to a metal case;
i.e., the grounds are all connected together.

In ON4UNs  5th edition, he appears to recommend that the common connector (the one to the
braid-breaker 7:5 matching transformer) not be tied to the grounds of the two output connectors,
and shows a picture of his splitter/combiner which appears to be in a plastic box.

Should I construct my RX splitter with all three shields connected together,
or should I isolate the common (middle) feedline shield from the other two?
This is to be used in the shack to feed tor receivers.

Terry Zivney, N4TZ