1- Install
Advanced Templates
2- Create an admin only field in your Admin CP and note its field number.
3- Edit your postbit template and add there (to relevant place):
PHP Code:
[[($bbuserinfo[usergroupid]==6 OR $bbuserinfo[usergroupid]==5 OR $bbuserinfo[usergroupid]==7)]]
$post[fieldX]
[[/($bbuserinfo[usergroupid]==6 OR $bbuserinfo[usergroupid]==5 OR $bbuserinfo[usergroupid]==7)]]
Replace X with the id of your field.
This will display this field to your Admins/Mods and S.Mods in postbit..
Enjoy.