Include div block, only in first particle instance (Twig, Joomla)

[webarion]

I create my particle. And there can be several particles on a page.
The particle must have a dynamic modal window. And the modal should be one per page, created by the first particle only. All other particles must work with the modal window created by the first particle.
It's possible to do this through JavaScript, but the question is, is it possible with twig to know the particle's instance number to prevent the modal block from being re-created?

[webarion]

I found a way to detect that the particle instance is the first one on the page:

{% if gantry.config.index.particles.myParticle|keys|first == id %}
  {{ 'This first my Particle: ' ~ id }}
{% endif %}

Now the question to the connoisseurs is this the right way? And is there a better solution?

[webarion]

So, I found a solution that suits me. And this solution is in the documentation:
https://docs.gantry.org/gantry5/advanced/css-js-twig

{% pageblock body_top %}
  <div class="MyModalBlock"></div>
{% endpageblock %}

This way, only one instance is loaded <div class="MyModalBlock"></div>, even if there are multiple instances of the same particle on the page.