You've gotten good responses from my collegues - there is a status in the GSMLS called "US" - "under contract, continue to show". To the public, it appears active, an agent can see that it has a contract. To Mary's point, some buyers will not want to get involved if an accepted offer is in play, but the status is in place to allow you to acknowledge you are under contract, and continue to show.
If you do this, exercise care. I have also seens situations in which a good deal, with a qualified buyer has gone bad because the buyer was so rattled by the property continuing to be shown.
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