Greetings!

Thank you for this amazing toolbox.
This might be a very basic question related to task-fMRI design:

I have two groups of participants: Patients and Control with covariates Age, Gender and Education level.
I have two more sub-groups which include dividing participants with respect to a score and named as Group A and Group B.
I have added covariates defined as GroupA_age, GroupB_age, GroupA_education, GroupB_education, GroupA_gender and GroupB_gender. I have mean centred the age and education covariates.

Furthermore, in this work, I am using ROI-to-ROI analysis and want to understand the differences in connectivity between the two analyses, namely weighted GLM and gPPI.
 
To begin, I'd like to know which between subject contrasts I should employ in my second level analysis to comprehend:

1. Patients > Control in terms of functional connectivity.
2. Only Group A effect, and
3. Only Group B effect.

In addition, when I try to choose GroupA and related covariates, I receive a warning suggesting that the design may contain an invalid model.

Thank you in advance 

Regards,
Abhishek