Group custom fields

Hi,
I need a solution for the following example:

Within an article about a tour of a musician there should be the possibility to enter the tourdates in custom fields. The problem is we have the key multiplied.

Date: 12th September
Date: 17th September
Place: One
Place: Two

The output should be:
Date: 12th September – Place: One
Date: 17th September – Place: Two

How can these values grouped together? We need custom fields because we want to display the values in widgets too.

Do you have any solution with custom fields or maybe an existing plugin?

Regards
Micha

PS: We don’t want to give the key a suffix like date1/place1!