Deleting People's Second Name

In column G of my excel 2003 worksheet named: Data, I have a list of people's first names. These names were extracted from an external database.

Some of the first names actually contain peoples second names or partner's names.

Example:

John & Jill
James and Sue
Kerrie-Anne

Joanna Lyn

I need a macro to please delete people's second name.

So in the example above I need to keep all names that are joined by: & or and or - (such as John & Jill, James and Sue, Kerrie-Anne).

Also, in the example above I need to delete all names that are joined by a <space> (such as Joanna Lyn).