Setting up Parameters to show specific info for each choice

[user1414]

I've prepared a report where the parameters are set up so the user can select a site (State) and select a county within that state, however I do not want them to have to scroll through and find their counties for their states or type it in manually.

Question:
Is there a way to ----Create a parameter for multiple sites so each time one is chosen they only see own their counties.