I would like to know if there's a way to put several images in a single event of a XML file generated from a BD PGS/SUP file. That original SUP file had one overlapping of subtitle lines in different positions and now, since I want to translate these subtitles and render another SUP file for that translation with identical display time and the most similar positioning as possible, I would like to know the best way to deal with overlapping.

To make it more simple: Let's assume I just want to create a sup file with only 3 lines:

1. This is line 1 [0001.png]
2. This is line 2 [0002.png]
3. This is line 3 [0003.png]

and I would like to make them appear as follows:

1: From 00:00:08:00 to 00:00:12:00, at the bottom.
2: From 00:00:10:00 to 00:00:14:00 at the top.
3: From 00:00:16:00 to 00:00:20:00 at the bottom.

As it can be seen, line 1 and line 2 are required to overlap from t=8s to t=10s.

My first attempt has been the following one:

HTML Code:
<?xml version="1.0" encoding="UTF-8"?>
<BDN Version="0.93" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="BD-03-006-0093b BDN File Format.xsd">
  <Description>
    <Name Title="Test1" Content=""/>
    <Language Code="eng"/>
    <Format VideoFormat="1080p" FrameRate="23.976" DropFrame="False"/>
    <Events Type="Graphic" FirstEventInTC="00:00:08:00" LastEventOutTC="00:00:20:00" NumberofEvents="3"/>
  </Description>
  <Events>
    <Event InTC="00:00:08:00" OutTC="00:00:12:00" Forced="False">
      <Graphic Width="560" Height="70" X="680" Y="1000">0001.png</Graphic>
    </Event>
    <Event InTC="00:00:10:00" OutTC="00:00:14:00" Forced="False">
      <Graphic Width="560" Height="70" X="680" Y="10">0002.png</Graphic>
    </Event>
    <Event InTC="00:00:16:00" OutTC="00:00:20:00" Forced="False">
      <Graphic Width="560" Height="70" X="680" Y="1000">0003.png</Graphic>
    </Event>
  </Events>
</BDN>
However, after converting it using BDSup2Sub, I don't obtain the desired result, since it automatically removes the second line from t=8s to t=10s in order, precisely, to avoid overlapping.

Since it looks like I haven't written it properly (I don't understand how such temporal events actually work if the timeline isn't progressive), my second attempt has consisted on combining both 0001.png [560x70] and 0002.png [560x70] using an image editor in a file 0001+0002.png [560x1060], such that "This is line 2" is on the top and "This is line 1" is on the bottom, and then I write:

HTML Code:
<?xml version="1.0" encoding="UTF-8"?>
<BDN Version="0.93" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="BD-03-006-0093b BDN File Format.xsd">
  <Description>
    <Name Title="Test2" Content=""/>
    <Language Code="eng"/>
    <Format VideoFormat="1080p" FrameRate="23.976" DropFrame="False"/>
    <Events Type="Graphic" FirstEventInTC="00:00:08:00" LastEventOutTC="00:00:20:00" NumberofEvents="4"/>
  </Description>
  <Events>
    <Event InTC="00:00:08:00" OutTC="00:00:10:00" Forced="False">
      <Graphic Width="560" Height="70" X="680" Y="1000">0001.png</Graphic>
    </Event>
    <Event InTC="00:00:10:00" OutTC="00:00:12:00" Forced="False">
      <Graphic Width="560" Height="1060" X="680" Y="10">0001+0002.png</Graphic>
    </Event>
    <Event InTC="00:00:12:00" OutTC="00:00:14:00" Forced="False">
      <Graphic Width="560" Height="70" X="680" Y="10">0002.png</Graphic>
    </Event>
    <Event InTC="00:00:16:00" OutTC="00:00:20:00" Forced="False">
      <Graphic Width="560" Height="70" X="680" Y="1000">0003.png</Graphic>
    </Event>
  </Events>
</BDN>
The problem is now that after rendering the SUP file the second and the third line aren't shown. Well, they actually are shown but in the blink of an eye, probably some few frames, but too far to be 2 seconds long each one... I guess it must be that BDSup2Sub doesn't support frame-connected subtitles lines. I've also tried to separate them 1 frame, but it also fails.

What I would actually like to achieve is make them appear overlapped as separated images, because I think this is the simplest way and because I think this is the way the overlapping subtitles are rendered.

Any suggestion?

Thanks in advance!