Without knowing your domestic situation / location...

Could you do the ex Dub routed DUB-LHR (overnight under 23 hours London and pick up the kids) LHR-USA-LHR (drop the kids) - DUB.

Use the 241 to book two tickets for the kids on the same flights as you LHR-USA-LHR.

You could then check all the luggage back to LHR on their allowances and either get them met at LHR and then go back airside yourself, or be naughty and don't.

Many of the ex DUB fares work fine open jaw so you would do DUB-LHR NYC // IAH-LHR-DUB if this works.