Is it possible to find out the current cursor position on the screen?

Example:

On "Enter" process="xyz.txt"
xyz.txt
if cursorposition is row1, col3
Goto SKIP_PROCESS
endif
//InputScript processing (Screen/Enter Blocks)
.............
Label SKIP_PROCESS

Yes, this is possible. There are a number of system variables
&V[_cursor...] that you can use.
Please have a look at the GuiXT Debug window when the InputScript starts, in order to select the appropriate ones.