Yes GEDCOM is a "linkage" based system and that is what I mean by "connect" aka "link".
So I have two complete individuals in my database.
1) The original individual with all vetted information.
2) The second "maybe I think is the same person"
The #2 person would have what ever information I find that I'm not 100% sure is correct, maybe this information came froma letter that said "Joe was born on May17, 1814" but there are 4 Joe's in the family group. One of them could have been born in 1814 but I have nothing to go by other than the letter, I do have lots of other information about this "Joe"Joe #1 (already in my DB) like his marrage information or death, that I know is >99% correct. So until I actually have better assurance of Joe #2 being = Joe #1, I create an ALIAS JOE and Link or connect #1 and #2 using the ALIA tag in my GEDCOM DB.
Your example is in the v5.5.1 GEDCOM and defined as:
An indicator to link different record descriptions of a person who may be the same person.
EDIT: This only works for same person relationships. But you could make it work for your need which is create a dummy "Right Joe" son of Bill with little or no information that you would fill in as you get >99% but keep "Not sure Joe" information in the ALIA connected individual.