it occured to me that you may be useing the term 'wisper' in place of what mIRC would call a query or privit msg, and by userlevel u actualy mean rank in a channel, op, voice etc

if this is the case, there is one issue, in that in a privit msg event with a specific person, mIRC will not know which channel your refering to in regards to access, u could either define the channel name yourself and check it, or you could loop though all the common channels between you and $nick.. the following example is if u wish to define a channel specific privit msg event:

on *:TEXT:*:?: {
  if ($nick isop #channel) {
    if ($1 == !trigger) { msg $nick * info }

in this case, mIRC will check to see if $nick is op in '#channel' (u will need to change #channel to the name of the channel uw ish to check) and if they typed '!trigger' (u will need to replace this with whatever u wish the triger to be) it will msg $nick with info (replace info with the test u wish mirc to send to them)

hope this is what u were looking for, if not refer to my previous post