Hello Jeff, 

thanks again for your very useful advice. I am in the first case. I haven't coded yet any of the two SR, but simply imported the references from Zotero. The two SR have some criteria in common: one is on the Welfare Economic effects of GMO and the other on trade effects of GMO regulation.  Following the example on the youtube tutuorial I see that both have same criteria of date exclusion, geographical coverage sand exclusion on language,  while of course the criteria 'exclusion on topic and inclusion based on title and abstract ' differ.

So to be sure I understand what you say, the best way is to export one into the other, ru the duplicate checking and then coding ( I wil have in total 6 exclusion/inclusion criteria)? 

Thank you so much again for your help. 

Best, 

Maria