How to capture part of string into a variable?

Hi,

I need to capture a part of a string of a response to a variable.

In this case I need to capture (and re-use it in other requests and responses), only the part after "WNG_BlobStore_1/" .

See attached screenshot. Only the yellow marked part needs to be captured.
I have tried capturing it using a variable (@blob_id), but this captures the whole ContentReference.

Is there anyway to do that? I think it's possible with regular expressions, but not sure.

Thanks,
Mathijs