Using Regex To Filter Out Guid's In String?

I'm using a certain regex to know where there a certain string values in a string:

Regex: C[([A-Z][0-9])]
String: =C[C3]+(C[C3]-C[C5])*(C[C3]-(C[C5]+C[C3]))

This gets every C[blabla] value out of that string and when I ask for group(1), I don't even have to cut of the "C[" at the start and the "]" at the end.Now I want to do this but instead of using the C[] placeholder, I'm using G[] and so not a "C3" like string in that placeholder, but a guid so I get these:

Regex: G[[{|(]?[0-9a-fA-F]{8}-([0-9a-fA-F]{4}-){3}[0-9a-fA-F]{12}[)|}]?]
String: =Guid[92716d13-01d1-447b-be3f-c090fed6336c]+Guid[92716d13-01d1-447b-be3f-c090fed6336c]

When I check the regex, it matches a guid perfectly, but I don't get any matches when I use more than just one guid (or when I add characters before or after).I left out the "^$" so it doesn't define a start and end anymore, but that didn't seem to be the problem.