1 textfield and 3 radiobuttons instead of 3 texfield

Hi!
I have 3 gridviews with 3 SQLDataSources that i want to search from. I have created 3 texfields with a search function that works fine, but then i figured that is not very pro and effective to have 3 searchfields.
I was thinking of using only one texfield, and with radiobuttons choose what SQLDataSource to query from.
What is the best solution to do this? 
...