With the current release we don't have default wildcards, but you can implement your own by using Regex. You can create a new class and inherit Telerik.Pivot.Core.Condition. You'll notice two important methods there: CreateInstanceCore and CloneCore. In the first one you should create a new object from this class and in the second one you can copy all of your properties. The other very important method is PassesFilter where "the magic happens" - this is the place where you can match your regular expression.
To illustrate this we have prepared a simple project for you - please check it and inform us if you have any problems or concerns. If you want to use wildcards you'll have to add some more code - replace the "*" with ".*" on all places, add escape characters to the special regex symbols, etc...
Hopefully this helps.
the Telerik team