It is possible. I did it with all import plugin. In excel I used textjoin to put the required delimiters. The custom field you need is woosg_ids.
the data inside will look like
1000/0,1001/0,1002/0,1003/0,1004/0,1005/0,1006/0,1007/0,1008/0
1000s and up are product ID
s