Hi,
A variation of the approach mentioned by Marsha is to commit NameMapping as soon as it was changed, and notify others so that they can pull new file before they change something in their local copies.
P.S. Merge is a price that you are paying for the possibility to use local copy of the sources. Merging always is risky and dangerous because there is always a chance that automatic merge will do something incorrectly. So the more often you will commit, the safer you and others will be. (Note, that it is quite OK to commit the code that is not final but intermediate not working yet. Just make sure that this code will not be called/executed until you complete it.)