What I am thinking you mean, is that you have a trusted user list for receiving DCC files from, that will ignore all DCC sends from untrusted users (those not in the list), but will allow you to receive DCC files from those that are trusted.
However, the ignore feature in mIRC pretty much can do this already.
Simply use /ignore -d *!*@* to ignore all DCC's from any address, and then use /ignore -x nicknameoraddress to exclude that user/address from being ignored.
/help /ignore will show you all the ignore switches.
