You can link them but you're not going to be happy, linking in Cd is dubious at best.
Stupid question from me, can I ask why you don't want them embedded?
I am trying to keep the CDR file size down. I successfully used Ventura Publisher for 20 years. There I could choose to leave the picture files external to the publisher document. In creating a 28 page magazine, I was able to produce manageable PDFs for the printer.
Now with CorelDraw 2018, every time I add a picture file internally to the CDR the file size jumps. At the moment, it is over 1GB. The PDF size is out of control.
But I just tested a CDR. With no JPG, the file size is 1991KB.
Adding a JPG of size 5400KB to the CDR, leaving it external, increased the size of the CDR to 16900KB.
I don't get it.
The problem is creating a press quality PDF for the printer. Way too big.
Ventura was a program that knew how to properly link images and format long documents. CorelDRAW will not make you happy with linking images, the best thing you can do is to import, properly size and set resolution for your images in CorelDRAW. Then use the proper PDF publishing settings when exporting. In reality your file content and PDF will be the same as when you used Ventura. The CDR file uses a lossless comprression that is very good and does not take up much space, I have 3GB (in memory) files that take up 200MB on disk.