Question Summary:
Will an individual leading a salaat in jamaat have to specifically mention women in their niyaat in the event that women join the jamaat?

Question Detail:

Will an individual leading a salaat in jamaat have to specifically mention women in their niyaat in the event that women join the jamaat?

Answer :

In the name of Allah, Most Gracious, Most Merciful
Assalaamu `alaykum waRahmatullahi Wabarakatuh
It is compulsory upon the Imam leading a congregation of males and females to make intention to lead the females in salah.
And Allah knows best
Wassalam
Mufti Ebrahim Desai
Darul Iftaa, Madrassah In'aamiyyah