Wrapping divs around a group of neo blocks

Question

How can I wrap a div around certain neo fields based on what appears before or after them?

Basically I want to wrap a container div around a set of items (text based objects) only at the start and end of these objects but whenever they appear. Sometimes they might have one item other times they migjt have several.

I started with this but I am a little stuck

{% for block in entry.contentBuilder3.level(1) %}
      {% set type = block.type.handle %}
      {% set nextType = (not loop.last ? type) %}
      {% set prevType = (not loop.last ? type) %}

      {% if type in ['heading', 'body', 'downloads', 'textLinks' ]  %}
       {{ nextType }} :: {{ prevType }} this is a first child
        <div class="max-w-2xl // min-w-75 // mx-auto //  //// px-6 // border //">
      {% endif %}

{% if prevType in ['heading', 'body', 'downloads', 'textLinks'] %}
      </div>
    {% endif %}

The above code currently wraps a div around each instance of the array not one around the group.

UPDATE:
After Marions helpful answer, I was unable to solve exactly with her method, but it did put me on the right tracks to solve it like so;

{% set inTheDiv = false %}
{% set nextType = null %}
{% set prevType = null %}

{% for block in entry.contentBuilder3.level(1) %}
  {% set type = block.type.handle %}
  {% set nextType = (not loop.last ? block.next.type.handle) %}
  {% set prevType = (not loop.first ? block.prev.type.handle) %}
  {% set fullWidth = block.fullWidth|default() %}
  {% set textBlockArray = ['heading', 'body', 'downloads', 'textLinks', 'pullQuote', 'callToActionText'] %}

  {% if type in textBlockArray and nextType in textBlockArray and prevType not in textBlockArray %}
    <div class="mx-auto // max-w-2xl border border-red //// py-4">
  {% endif %}

  {% switch type %}

    {# BLOCK TYPES CONTNET/TEXT #}
    {% case 'heading' %}
      {{ sectionSpacing }}
    {% include '_includes/matrix3/heading' %}

    {% case 'body' %}
      {% include '_includes/matrix3/body' %}

    {% case 'pullQuote' %}
      {% include '_includes/matrix3/pullQuote' %}

    {% case 'downloads' %}
      {% include '_includes/matrix3/downloads' %}

    {% case 'textLinks' %}
      {% include '_includes/matrix3/textLinks' %}

    {% case 'callToActionText' %}
      {% include '_includes/matrix3/callToActionText' %}

    {% case 'quote' %}
      {% include '_includes/matrix3/quote' %}

    {# LAYOUT BLOCKS #}
    {% case 'tabbedContent' %}
      <div class="-mx-6 //// {{ block.sectionSpacing }}">
        {% include '_includes/matrix3/tabbedContent' %}
      </div>

    {% case 'tiles' %}
      <div class="{% if fullWidth == true %}-mx-6{% else %}mx-auto // max-w-4xl flex{% endif %} //// {{ block.sectionSpacing }}">
        {% include '_includes/matrix3/tiles' %}
      </div>

    {% case 'tileWithImage' %}
      <div class="{% if fullWidth == true %}-mx-6{% else %}mx-auto // max-w-2xl{% endif %} //// {{ block.sectionSpacing }}">
        {% include '_includes/matrix3/tileWithImage' %}
      </div>

    {% case 'textWithImage' %}
      <div class="mx-auto // max-w-2xl //// {{ block.sectionSpacing }}">
        {% include '_includes/matrix3/textWithImage' %}
      </div>

    {% case 'textWithVideo' %}
      {% include '_includes/matrix3/textWithVideo' %}

    {% case 'textWithText' %}
      {% include '_includes/matrix3/textWithText' %}


    {% case 'statistics' %}
      {% include '_includes/matrix3/statistics' %}

    {# MEDIA BLOCKS #}
    {% case 'image' %}
      {% include '_includes/matrix3/image' %}

    {% case 'video' %}
      {% include '_includes/matrix3/video' %}

    {% case 'mediaGrid' %}
      <div class="{{ block.sectionSpacing }}">
        {% include '_includes/matrix3/mediaGrid' %}
      </div>

    {# CTA BLOCKS #}
    {% case 'callToActionFull' %}
      <div class="-mx-6 //// {{ block.sectionSpacing }}">
        {% include '_includes/matrix3/callToActionFull' %}
      </div>

    {% case 'callOutBlock' %}
      <div class="-mx-6 //// {{ block.sectionSpacing }}">
        {% include '_includes/matrix3/callOutBlock' %}
      </div>

  {% endswitch %}

  {% if type in textBlockArray and nextType not in textBlockArray and prevType in textBlockArray %}
    </div>
  {% endif %}

{% endfor %}

Answer 1

I always think of this sort of thing as a finite state machine. Your states are whether or not you are in the div, and for each block, you change state or not depending on what state you are currently in, and what that block type is. Like this:

{# initial state: not in the div #}
{% set inTheDiv = false %}

{% for block in blocks %}
  {# should this block be inside the div? #}
  {% set isInsideBlock = block.type.handle in ['heading', 'body', 'downloads', 'textLinks'] %}

  {% if isInsideBlock and not inTheDiv %}
    {# state change to inTheDiv #}
    <div>
    {% set inTheDiv = true %}
  {% endif %}
  {% if not isInsideBlock and inTheDiv %}
    {# state change to not inTheDiv #}
    </div>
    {% set inTheDiv = false %}
  {% endif %}

  ... output your block stuff here
{% endfor %}

{# done with blocks, so close the div if necessary #}
{% if inTheDiv %}
  </div>
  {% set inTheDiv = false %}
{% endif %}

The whole finite state machine may seem like overkill, but you can handle a lot of complexity this way.