Need help with SAML Response Mapping Advanced

[RaiRe22]

I want to map a User group based on the content of an attribute.

My attribute is the departement. If non empty group A, if empty group B.

I tried different ways using regular expressions and I'm not able to make it work.

For now I have : 

SAML Attribute : http://schemas.xmlsoap.org/ws/2005/05/identity/claims/department

SAML Value : .+

Resulting Value : Group A

SAML Attribute : http://schemas.xmlsoap.org/ws/2005/05/identity/claims/department

SAML Value : ^$

Resulting Value : Group B