match formula to add a new criteria

I have an existing file with two worksheets. Basically what is does is Lookup sheet contains my source data. Whenever Doctor's name is entered in "Data" sheet, it will match with the source. I have already have the existing function but I added a new column in my data sheet called "group" and I want it to be added in my existing function.

Also, my current function returns value even if no exact match is found, like if I enter "Mike" which is not found in my lookup sheet, it is giving a result. I want if no exact match is found it returns as "null" or whatever is appropriate..