is it possible in suiteCRM
Version 7.5.1
Sugar Version 6.5.20 (Build 1001)
is it possible hidden some function (create Workflow for example) only for some group of user ?
It is possible but I think you would need to custom code it yourself. I did something similar in the following blog post maybe this will be of help to you:
http://sugarmods.co.uk/make-an-edit-view-field-read-only-based-on-user-role-sugarcrm-ce/