Highlight previous bullet in navigation bar for beamer frame

I’m also using a theme which displays bullet in the navigation bar, each corresponding to a slide, and fills the bullet point corresponding to the current slide. Certain slides in my presentation are very short, because they are the continuation of the previous slide, and I would therefore like them not to contribute an extra bullet point. For example, in

begin{frame}{Some frame}
This is a frame
end{frame}

begin{frame}{Some frame II}
This is frame is short, and is meant to conclude the topic of the previous one
end{frame}

begin{frame}{A new frame}
Here I'm discussing something new
end{frame}

I would like that when currently viewing Some frame II the bullet point that is highlighted in the navigation bar that is the same as for Some frame, and in A new frame the next bullet point is highlighted.

This is what happens when you use framebreak, but I don’t want to use this because I also want to pause the frame in several places (and also want to manually control where I split the frame). I’ve found ways to get no new bullet point for some frame, but not to keep the one from the previous frame highlighted.

I would be very grateful for any help.

Here’s a MWE:

documentclass[10pt,xcolor={usenames,dvipsnames}]{beamer}

usetheme{Berlin}

makeatletter
setbeamertemplate{footline}
{
  leavevmode%
  hbox{%
    begin{beamercolorbox}[wd=.2paperwidth,ht=2.25ex,dp=1ex,center]{author in head/foot}%
      usebeamerfont{author in head/foot}insertshortauthor
    end{beamercolorbox}%
    begin{beamercolorbox}[wd=.6paperwidth,ht=2.25ex,dp=1ex,center]{title in head/foot}%
      usebeamerfont{title in head/foot}insertshorttitle
    end{beamercolorbox}%
    begin{beamercolorbox}[wd=.2paperwidth,ht=2.25ex,dp=1ex,right]{date in head/foot}%
      usebeamerfont{date in head/foot}insertshortdate{}hspace*{2em}
  end{beamercolorbox}}%
  vskip0pt%
}

title[title]{title}

author[author]{authorinst{1}}

institute[institution] % (optional)
{
  inst{1}%
institution
}

date[date] % (optional)
{date}

begin{document}

begin{frame}
  titlepage
end{frame}

begin{frame}{This talk}
  tableofcontents[pausesections]
end{frame}

section{Section 1}
begin{frame}{Some frame}
  This is a frame
end{frame}

begin{frame}{Some frame II}
  This is frame is short, and is meant to conclude the topic of the previous one
end{frame}

begin{frame}{A new frame}
  Here I'm discussing something new
end{frame}

section{Section 2}
begin{frame}{Some frame}
  This is a frame
end{frame}

begin{frame}{A new frame}
  Here I'm discussing something new
end{frame}

end{document}

section{Section 2}
begin{frame}{Some frame}
  % Use a single frame => no frame counter stepping/bullet change
  only<1-3>{%
    This is a frame% Slide 1
    %
    pause
    
    Here is some more stuff - beautiful stuff!% Slide 2
    
    pause
    
    includegraphics[height=3baselineskip]{example-image}% Slide 3
  }
  only<4>{%
    % Slide 4
    This is frame is short, and is meant to conclude the topic of the previous one
  }
end{frame}