DoorDash is telling employees not to connect with their counterparts at Instacart on LinkedIn. Jason Henry/Bloomberg via Getty Images

DoorDash employees might have to make fewer LinkedIn connections as a result of their employer's $17 billion deal to buy Instacart.

The food-delivery service told employees as much in an internal question-and-answer document filed with the SEC on Thursday.

"Can I connect with Instacart employees on LinkedIn?" reads one of the questions in the document.

"Not at this time," the answer says. "Please do not request any new connections with any Instacart employees on LinkedIn, even if you have a prior relationship."

The guidance shows that a pending takeover can change life inside the companies involved, sometimes for long periods.…