Ensuring what tier my provider is in

Is there a way to find out in what tier your provider is?  I have asked several of my providers in what tier they are, and most reply, "I don't know."  Short of calling one of your many 800 numbers to ask BCBSIL directly before I make appointments, is there a way I can find this out myself?  We had many Tier 1 providers with our former insurer, and their tiers were listed in the provider listings online.  Can anyone help me do this?  Thanks!