A few changes to promote_users capability

I want to give 2 users promote_users capability. I want to give them promote_users capability for mainly forum roles.

I would like to make a few changes to default promote_users capability.

Please check this image http://s4.postimg.org/g8oghi7kt/site_roles.jpg I would like to completely remove site roles so that they could not promote themselves or other users. I mainly want this for 2 users.

I shall be thankful to you if you also give me a code that will let me make above mentioned changes but it applies to entire role instead of a few users. I may need this in the future.

I also would like to have a code that will hide 1 or more site roles like editor and author instead of entire site role menu so that moderators could not promote themselves or others to these roles. Again codes for both more than 1 users and entire role.

Sorry for my poor English. I have tried to explain the changes i want in best way. If you could not understand, i shall try again.

Thanks
Umar

https://wordpress.org/plugins/user-role-editor/