Python's re module and genealogy problem

[BrJohan]

For some genealogical purposes I consider using Python's re module.

Rather many names can be spelled in a number of similar ways, and in 
order to match names even if they are spelled differently, I will build 
regular expressions, each of which is supposed to match  a number of 
similar names.

I guess that there will be a few hundred such regular expressions 
covering most popular names.

Now, my problem: Is there a way to decide whether any two - or more - of 
those regular expressions will match the same string?

Or, stated a little differently:

Can it, for a pair of regular expressions be decided whether at least 
one string matching both of those regular expressions, can be constructed?

If it is possible to make such a decision, then how? Anyone aware of an 
algorithm for this?