Send your groups to Mediaflow

On the same page, under Group Attribute Statements (optional):

Under Name, enter exactly: http://schemas.microsoft.com/ws/2008/06/identity/claims/groups
Keep Name format at Unspecified.
Under Filter, choose Matches regex and enter .*

The Group Attribute Statements row with Mediaflow's groups attribute name and the filter Matches regex.

.* sends every group the user belongs to. If the groups Mediaflow needs share a prefix, you can choose Starts with and enter the prefix instead.