[Remind-Fans] Function to extract the start of an UNTIL/THROUGH range?

[Tim Chase]

If I have a reminder like

  REM Jul 12 2022 THROUGH Jul 19 2022 \
    MSG Runs [magic()] through [triguntil()]

and I run it today (2022-7-13), what I'd like is

  $ rem
  Reminders for Wednesday, 13th July, 2022 (today):

  Runs 2022-07-12 through 2022-07-19

with the first date being the one defined as the beginning of the
event (2022-7-12) rather than today's date (2022-7-13).  I've tried
$T, $U, and a scattering of other trig*() functions like trigfrom()
but haven't been able to find one that extracts that first/specified
date.

Is there something I'm missing?

Thanks!

-tkc