"The first four names (in the 4x100m relay pool) have to be your top four finishers at the championships," the women's Olympic coach said, naming 100m winner Carmelita Jeter, runner-up Tianna Madison, Felix and Tarmoh as automatic selections for the six-member relay pool.
Felix and Tarmoh finished in a dead heat for third and face a run-off or a coin flip to decide who takes the final individual 100 spot on the U.S. team.
"But the result of the 100 metres will not affect the relay pool at all," Deem said.
The final two relay pool spots will be chosen after the trials end on Sunday and will likely go to athletes who have not made the team in individual events, she said.
Felix and Tarmoh have until Sunday to either participate in a runoff or coin flip unless one of them withdraws from the 100.
"I think all of us need to take a step back and let these young women focus on the 200, make the team and then everybody sit down and we go from there," Deem said.
All four 100m finalists have entered in the 200, for which qualifying starts on Thursday. The final is on Saturday.
At the halfway point of the trials, Deem, along with men's Olympic coach Andrew Valmon, said the United States would bring a strong team to London but both shied away from predicting it would meet the 30 medals goal that USA Track and Field executives have set for the Games.
"We had a couple of mishaps here and there but we had some surprises," Valmon said.
Valmon was particularly impressed by Ashton Eaton's decathlon world record and 2012 world-leading performances by LaShawn Merritt in the 400 and Reese Hoffa in the shot put.
He also praised Justin Gatlin and Tyson Gay's 1-2 finish in the 100.
"There are a lot of opportunities to get those 30 medals," Valmon, a two-times Olympic 4x400 relay gold medallist said.
"I think the big thing is reclaiming the sub-45 seconds," Valmon said of 400m contenders Merrett, Tony McQuay and Bryshon Nellum.
"For years we have been a dominant nation, and we have got the three guys who are 44-second quarter-milers and they are going to go out there and compete for medals. And they are young."
The three will afford the U.S. another chance for gold in the 4x400 relay, even though former Olympic champion Jeremy Wariner failed to make the team.
Josh Mance and Manteo Mitchell, who also ran under 45 seconds in the final but finished out of the top three, will have a chance to run in the relay.
Deem was pleased with Olympic discus champion Stephanie Brown Trafton's performance at the trials and that of former world 400 champion Sanya Richards-Ross.
Brown Trafton's victory in the rain was not a personal best, but a timely confidence boost, while Richards-Ross, the year's fastest in the 200 and 400, was running as well as she ever had, Deem said.
"We have a great group of women who have been there, have experience," the coach said. "And I think that is really going to help us in the medal count."