Is it permissible for girls to gather to discuss religious matters in one room with the door open, without a male guardian (mahram) present with them?

It is permissible to sit with religiously observant women who wear the legal hijab (definition) and are accompanied by a mahram (definition) if there is a need for it. However, it is preferable to avoid repeating this unless it is absolutely necessary. One must be cautious of temptation by blocking all means that lead to it, especially considering women's display of their adornments (tabarruj) and their non-adherence to the legal Islamic etiquette in conversation.