Thread Group A: use challenge-response to generate user token. Save as JMeter property. Thread Group B: Run several samplers, one of which uses that token in a header.
Of course, the easy thing to do is run A, then B.
But let's say I want to use a "modular" approach and run only B.
I thought I recall seeing either in SO or Blazemeter that the JMeter object model allows one in a JSR223 Sampler to reference other samplers, even in another thread.
Other ideas also appreciated.
JSR223 Sampler cannot "call" another sampler neither from current nor in another Thread Group.
The only way of implementing this I can think of is storing the "common" logic as a Test Fragment and calling it where required using Module Controller