You can but my understanding has always been that when it’s two separate PNRs that are linked, you can’t clear until DoD and the second person will be on the list at their status level (so bottom if just a member).

That said I have gotten to the gate early in such a scenario and the gate agent did something so that she appeared right after me as if we were on the same reservation instead of linked reservations (I was on a work ticket and so had to book hers separately).

This was in 2019 (and we actually cleared the SEA - RDU into F) so not sure if they’ve changed something to prevent a GA doing that these days