Using dropdown list, 2 search buttons, 2 textboxes and from and to-date calender

Is there a way to use 2 radio buttons one for search by EmpId and another one for search by Loan# and then one search button? 
Right now I have two textboxes and two search buttons.
I also need help on how to tie Audit Category from dropdown list to the search buttons
I am using 2 gridviews  One for search result by EmpId and another for search by Loan#. 
When searching by Loan# there is no need to enter the AppDate. 
Here is my aspx code:


<div style="border: thin groove #C0C0C0; background-color: #DDEEFF;"> 
<br />
<span style="font-size: medium">
<asp:label id="LblAuditCat" runat="server" text="Audit Category:"></asp:label>
</span>
 
< ...