I need a RegEx Expression that will find the index in an array to use in a VB.net app.

I need a RegEx Expression that will find the index in an array to use in a VB.net app.

The array

Dim names() As String = {"Karthik AH", "Sandhya TT", _
"Shivangi JI", "Ashwitha GA", "Somnath OP"}

Conditions
Karthik A returns 0
Karthik AH returns 0
Karthiik AH returns -1
Karthik AS returns -1
Karthik return 0
Karthik OO return -1
Somnath OP returns 4
somnath op return 4

Case insensitive

If both initials are with the name it will compare both. If only one it will use just the first one.