'And Sanctify Him' - Son-in-law Kohen and Me'zuman

I have a son-in-law a Kohen, am I obligated to honor him with 'Me'zuman'('invites' where one is honored to invite the others to join him in birkat hamazon)? It seems to me logical that this rule applies only when everyone is equal - then the Kohen takes precedence, However in this instandce i am the host and therefore should have the right to choose who should get the 'me'zuman'.Therefore, my question is am I entitled to give it to whoever I wish.

Thank you for your question.

I would like to quote the Halacha on this matter as taught by Hagaon, Harav Amram Fried, shlita:

If there is a host and only one guest (who may be a Kohen at his father-in-law's house, or any guest) - One should Honer the guest with 'Me'zuman', this isn't obligatory, but rather as 'good advice' (עצה טובה). 

If there are several guests and among them a Kohen - you may give it to whomever you wish (However, the opinion of the Gra"z, is to give it to the Kohen guest, and if there is a queue, the Kohen should be first in line).

Wishing you much success.

Azmera Leshimcha 286