The access methods required for ini files prevent you from doing what you're looking for directly. One option is to use the -i switch in the /hload command, then search the hash table.
A couple of additional items that you may not have thought of, is that ini files are, realistically, limited to 64k in size. While it is possible to create and use ini files that are bigger than 64k, there is no guarantee that you won't have data loss. The 64k limit is a Windows limit not mIRC.
Also, by using an ini file, the file has to be opened and closed every time you access it, thus causing wear & tear on your hard drive and subjecting your data to the relatively slow speed of your hard drive vs. the speed of RAM in your system (which a hash table uses.)

less chance of it being lost on a mIRC crash/dc/etc. This is the set of scenarios that are normally handled by the ON DISCONNECT and ON EXIT events in my script.
The only way that a system could crash and not have at least one of those triggering is if there was a sudden power outage where the system had a complete power failure within (about) 2 seconds of the power supply failing.