1/4" f-jacks on splitter question

[jibberish]

my main question is in regards to the two split jacks on the pickup side of my splitter/buffer.
standard input jack wiring sems to always put the hot line to ground when an instrument/other input isn't plugged in.  It makes sense that you don't want to put open circuit noise into the high gain input end of a circuit.

Here's the problem: wired in parallel is also the unmodified thru signal jack from the pickup to the amp.
IF I wanted to make this dual-useable and be able to just use the buffer, what do I do with the thru-output jack, which in reality is identical to the guitar input jack. this guy is hanging open and I cant short it to ground being in parallel with the input to the buffer circuit. I briefly thought about several 2meg resistors and ..time for some other perspectives..heh

can I just leave the ground lug-when unplugged, ungrounded?(on th ethru out) and only ground the pickup input jack for unplugged state?