[request] Advanced XThreads Prefix Filter

[Jumper]

one question:

i have add one prefix for the language (pref_lang). values are:
1.german
2.english
3.german & english
4.other

but if somebody select "german & english"-filter, the single languages "german" and "english" are not included. i know, that´s normaly correct. but is there any solution, that if you select "german & english", that the other 2 values are included in the search-result?