All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The Criterion of being in seclusion with women according to the Jurists, is any meeting that is usually not free from suspicion.
An-Nawawi stated that "The presence of a boy from whom one is not ashamed due to his young age does not negate the (forbidden) seclusion. He gave an example of a two or three-year old boy. He said when explaining the Hadeeth that reads: “A man should not be in seclusion with a woman except in the presence of her Mahram.”: If a man sits in seclusion with a woman who is not a Mahram to him without a third person being present with them, then it is forbidden according to the consensus of the scholars. The same thing applies if there is with them someone whom one is not ashamed of due to his very young age, like a boy of two or three years of age, because his presence is like his absence.” [End of quote]
This indicates that if there is a boy who reached the age of distinction from whom one is usually ashamed (to do anything improper), then the condition of the forbidden seclusion is not met.
Therefore, if you feel that you are safe from temptation, then there is nothing wrong with the woman being in one room while you are in another room with the students. However, if you can look for better setup, then that is better in order to avoid any embarrassment, and to be free from any suspicion because a Muslim should avoid being in suspicious situations.
'Ali ibn Al-Hussayn narrated that "Safiyyah, the wife of the Prophet informed him that she went to visit the Prophet when he was observing I'tikaaf in the mosque during Ramadan. She spoke with him for a while, then she got up in order to return home, so the Prophet got up to accompany her. When they reached the entrance of the mosque, opposite the door of Umm Salamah, two Ansari men were passing by and they greeted him . He told them: “Do not hasten away! This is (my wife) Safiyah bint Huyay." Both of them said: "Subhana Allah, O Messenger of Allah.” And they felt saddened (that he had to explain so that they would not think evil of him ). The Prophet then said (to them): "Indeed, Satan reaches everywhere in the human body that his blood reaches. I feared that Satan may cast an evil thought in your hearts."
An-Nawawi said in his explanation: “This Hadeeth is evidence that it is desirable to avoid exposure to the suspicion of people, and to seek to be safe from it by giving valid justifications. When he does something which people may apparently resent, even though he did something that is right in principle, then he should clarify his condition in order to repel suspicion. Also, this Hadeeth is a proof that one has to be prepared in order to avoid the plots of the devil as the latter reaches everywhere in the human body as blood reaches, so one should be prepared to protect himself from the whispers and the evil of the devil." [End of quote]
Allah knows best.