NO, This is possible, refer here too....
Change Request Management scenario: Usual questions and known errors
27. Several managed system with same SID
In Solman 7.0 we cannot differentiate distinct systems with the SID, even if they are located in different domains.
In Solman 7.1 this issue will be solved by using the long SID functionality provided by SMSY, that is, systems in different transport domains with the same SID can be managed by charm, you only need to assign them to different technical system names in SMSY, see also note 1358071.
Thanks
Jansi