The link I gave has examples. Here is one of them:
{IF { Mergefield Gender } = "Male" "He" "She"}

converted to your use:


{IF { Ref Keyname} = "Jim" "5555 Odana Road"}
{IF { Ref Keyname } = "Mike" "215 South Hamilton Street"}

Those two would be placed in a Word document with no space between them (and no paragraph break). They only contain truetext; that is, they test for the text in the Keyname bookmark and give you something if there is a match. It is possible to nest another IF field as falsetext, but I find that to be cumbersome and there are limits to how deep you can nest IF fields. There are no limits of which I am aware on the number of IF fields you can have in a document.