Do you (or anyone

My situation is as follows: we have a number of different installation projects, all of which use custom dialogs (but one theme). Some custom dialogs are shared, other's aren't. Now I am having great difficulty creating new dialogs (based on existing ones as most of the time it is only a textual change). Often I end up overwriting dialogs or having my changes appear in the Dialogs\\<theme>\\Custom folder but not in my <installation project> folder.
What can I do to make life easier for myself??
Erik