Robust transform map to write on read only fields

[gdo]

Dear community,

Please help me with this complicated task :

- For records created by the discovery source "SG Azure" through the robust transform map, some fields in the List View and Form view must be set to 'Read Only'

Please not that the "Read Only" rule should only apply to records created by the Discovery source = SG-Azure. For exemple : fields for records created manually in the Class Server should be kept editable.

I made a data policy to make read only the fields (state, install status etc..). But I have two problems :
1) The list view is still editable.

2) At the import, as the fields is read only, my imports fails.

I use a data source through service graph connector into a robust transform map. I need to make a condition that makes read only only when discovery source = SG Azure. I am not allowed to write a script in the robust map.

Would you have any idea to put a condition on the robust map ?

Otherwise, I am thinking about ACL but I don't see how to allow the robust transform map to have the rights to overwrite the read only on the field dictionnary 
Can you see any other way in orer to not use ACL, if not how to give my robust transform map the role/rights to overwrite the read only 

Kind regards,

GDO

[gdo]

The ideal would be that data policy is always on unless for imports (as all imports have discovery source = sg azure)