Two simultaneous key-change events

[MJ Moody]

Is there a way to force lilypond to include two key changes back to back,
separated only by a \bar ":|".  I get the two simultaneous key-change event
error but would like to override or find a work around if possible.  The piece
goes from begins in b-flat major changes to e-flat major, it repeats back to
b-flat major and finishes in the key of e-flat major.  I am having trouble at
the repeat sign.  I would like to include the key change (b-flat) prior to the
repeat and the second ending key (e-flat) after the repeat.

My first solution was to use a spacer rest between these two key changes but
that created a new empty measure with a lot of open space.  I found guidance on
putting the key cancellation and key signature before the repeat bar, but am
unable to find out how to force the second key signature (the examples I found
went from g major to c major so they didn't need additional sharps or flats to
show up after the key cancellation/key signature change).

The input below works to generate the key of b-flat major and a natural on the
a.  But doesn't generate the second key signature after the repeat.

 \once \override Score.BreakAlignment #'break-align-orders = #(make-vector  3
           '(key
           span-bar
           breathing-sign
           staff-bar
           clef
         time-signature))
    \once \override Staff.KeyCancellation #'X-offset = #-4
    \once \override Staff.KeySignature #'X-offset = #-3
                \key bes\major \bar ":|"

    \key ees \major

I appreciate any guidance.
MJ