multi group comparison

Hi everyone,

I have the following measured (observable/manifest) variables:
  • two variables capturing two participant behaviours while solving a task
  • two variables that measure the participant's outcomes on that task
These variables are measured across different age groups.

My question is:

What could be a good method to investigate whether any of these four variables are measurement invariant across the age groups and whether their relationships are also measurement invariant?

Thank you,