how to wire a common volume on a switched jacks send return

[Renegadrian]

My intention is to build a fender-type pre a la fet2b before the class D amp from aliexpress I am waiting for.

I'd like to have a send return, both for using modulations inbetween, and to use the send as a pre out and the return as a power in.
I am going to use switched jacks.
the pre has its own master volume, so it would sit between the pre and the amp passing thru the jacks. now if I connect a jack in the send, the signal from the preamp would benefit of the volume control, and the amp would receive no signal.
in the other situation, the return would have no volume. otherwise I'd have to wire the volume on the amp side after the return jack but the pre would have no volume then.

now to cut story short, you got the situation, is there a way to share a single pot between the send and the return and how to wire those switched jacks!?
THX

[PRR]

For other reasons, it is not uncommon to need *both* a Send Level and a Return Level.

While this seems a drag, remember that commercial products can be priced $10-per-knob, so more knobs is a higher selling price, more chance to skim some profit.