Radio buttons and subordinate options

I often come across the situation where the user must make a high-level choice using radio buttons or dropdown, and - depending on that choice - different sets of subordinate options are presented.

Here's an example of the sort of thing from PUTTY where depending on the Connection Type, different parameters are entered. (This is a pretty simple case, where there's only two subordinate options and the type and number don't vary accordng to the primary option.

(And, if this was my design I'd have the radio buttons above the other options!)

I'm not keen on this approach because the changing subordinate options are something of a hidden affordance. A design using tabs for each "Connection Type" could work better, but using tab selection to control a 'mode' is very unintuitive.

I feel there should be a better way, but I'm unsure what it is.