Primary key column with null​ records

Hello everyone

I'll try to explain my problem with PowerBI.
I have 2 different datasets; dataset A is from incident management application, with unique incidentID. Dataset B is from project management application, where most (97%) of records have incidentID but few of them are null.

When I'm making report for customers, I need data from both application to create overall full-scale report, but also I need records with null incidentID from dataset B because they are also in scope, and have to be reported.

Is the only way to get this: import A and double B dataset, make a relationship A with B, and then add visuals from related A-B and separatey from non-related B?

Thanks in advance,

Petra