By the application of pyrethroids, you can enhance the resistance to neonicotinoids or vice versa. I read some information about how they can affect the same site of action, but I want more literature to be sure about this.
You can find a lot of useful information on pesticide resistance, cross resistance etc. on the FRAC homepage (Fungicide Resistance Action Committee) http://www.frac.info/ go to: publications and look at the 2014 FRAC code list. If two or more pesticides have the same FRAC code, than they will be cross-resistant.
Despite both insecticides had different modes of action, the degradation by means of the cytocrome P450 (e.g. oxidases) might involve the same metabolic routes. Here, I attached a link to a web page that would help you: www.irac-online.org.