Praise be to Allaah, and peace and blessings be upon our Prophet Muhammad, sallallaahu ‘alayhi wa sallam, and his household and Companions and those who follow him.
Menstruation is one of the signs of reaching puberty among women. Hence, if the mentioned girls perform Hajj this year, then they will have fulfilled the obligation of Hajj given the fact that they have attained puberty.
It is not obligatory on you to help them perform Hajj by paying the expenses. If you do this voluntarily, however, it shall be greatly rewarded.
If a woman menstruates during Hajj or before it, then she may perform all the rituals of Hajj or ‘Umrah, except for circumambulation of the Ka‘bah, for which purity is a requirement, according to the majority of scholars.
Allaah Knows best.