Complete Newbie PC/Mac question

[ErwinDenissen]

I’m afraid I don’t have an easy solution. I think most modern fonts that allow “stacked up” characters, contain OpenType features like glyph substitution (in the GPOS table). This topic explains how to add such features to your font with help of the OpenType Compiler:
Adding OpenType features

Another post, but IMO less relevant is:

Fonts generated by FontCreator have a great problem

I remember having this kind of problem too. In my experience it is NOT a FontCreator issue. In my case the problem was caused by glyphs which had a zero advance width. Setting the advance width to, say, 5 units makes hardly any visual difference. I hope this solves your problem.