Spelling and user dictionaries

[Chalkster]

Is it possible to set a spell check to use ONLY a user dictionary and ignore main dictionaries?

The reason is that I have various fields where predefined codes or groups of characters must be entered... these I can define in a user dictionary but I do not wish to allow "normal words" only these predefined ones.... a value list is not sufficient since multiple "words" can be entered in each field

I have a list of possible codes (approx 2000) which i would like to use to check data entry into these fields