I am an officially appointed Imaam at a Masjid. When visiting Ulama come to the Masjid, some trustees request them to perform Salaat without consulting with me.Is this correct?

Shariah has emphasized in honouring and respecting the right of an appointed Imam leading his congregation. We make reference to - among others - the following:
Abu Masood (Radhiallahu anhu) states that no person should become the Imam of a person in his place of leadership and no person should sit in the house of a person at his special place but with his permission. (Mishkaat pg.100; Me?raaj)
Whosoever enters the Masjid and he is more educated than the resident Imam then too the resident Imam is entitled to lead the salaat. (Fatawa Hindiyya vol.1 Pg.2; Rashidiyya)
It is Makrooh-e-Tahrimi for another person to perform salaat without the consent of the official Imam. (AAP.KE. Masaail or US KA HAL Vol. 2 Page 234) In view of the above it is clear that as the appointed Imam of the Masjid it is your right to lead the congregation. However, you are at liberty to give permission to a suitable person to lead the salaat.

And Allah Ta'ala Knows Best.

Mufti Ebrahim Desai