At least for the SDP MSP Build 14730 there is a problem to bulk add relationships between CIs in CMDB like Support Groups in MSP account and Services provided to other accounts. Neither API no XLS-file import does not allow to do it.

The import does not support to establish relationships between CIs from different accounts and the REST API in SDP MSP even does not have such the option at all. The only way is to add such relationships manually.

But in SDP, following 
https://www.manageengine.com/products/service-desk/sdpod-v3-api/cmdb/ci_relationship.html#add-custom-relationship-between-cis  

or 
https://help.servicedeskplus.com/api/cmdb/add_ci_relationships/add_ci_relationship.html
there is a good way to do it through API calls. 

How and when will it be possible to add relationships between CIs in bulk in any way?