[Adam]

MBilica is right. You won't find ruling that specifies anything about players' location during a technical foul free throw, because that's not where the rules differentiate. The distinction in the rules is between players along the lane and players not along the lane.

Someone who has always believed that players must go to the backcourt during these free throws, and who refuses to believe otherwise, will ask you for a rule reference. The only answer is to quote these two rules and ask them to provide you with a rule reference that provides additional restrictions on any free throws where no one gets to be along the lane.

And just to show I can predict the future:

The next response will be that it's just good game management to get them back there.

The alternative is to make players go to their benches in order to separate them, again for good game management or something.