Help with Venti Events Plugin
Sounds like a feature request for the developers of Venti, but this code should help you achieve what you need.

{% set upcomingEvents = [] %}
{% set upcomingEventIds = [] %}

{% for event in events %}
    {% if not event.eid in upcomingEventIds %}
        {% set upcomingEvents = upcomingEvents|merge([event]) %}
        {% set upcomingEventIds = upcomingEventIds|merge([event.eid]) %}
    {% endif %}
{% endfor %}