County champions Sussex will face leaders Yorkshire in the Twenty20 Cup quarter-finals while last year's runners-up Nottinghamshire host Kent.
Warwickshire will take on Lancashire and Worcestershire travel to Gloucestershire in the other games.
Lancs progressed when their game with holders Leicestershire was washed out.
Gloucestershire saw off Glamorgan and Kent beat Surrey to book their spots, while Yorkshire and Worcs qualified as the two best third-placed teams.
An intriguing final day of group games began with eight teams in contention for the remaining five spots - Notts, Sussex and Warwicks had already gone through as group winners.
It seems ridiculous that the champions have played only three games and only one of those has been 20 overs each
Leics skipper Jeremy Snape
Lancs did not have to do much to become the first to book their passage when a wet outfield meant no action at Old Trafford after several days of heavy rain.
For Foxes skipper Jeremy Snape it was yet more frustration with five of their eight games falling victim to the elements.
"It's devastating for us, we wanted to win to try to get through, but it was common sense to call the game off early," he said.
"It seems ridiculous that the champions have played only three games and only one of those has been 20 overs each. The weather's beaten us, which is really disappointing."
Lancs captain Mark Chilton said: "The whole competition's been a nightmare but the games we did play we've performed pretty well and we have to be happy with our position."
Twenty20 Cup quarter-final draw:
Sussex v Yorkshire
Nottinghamshire v Kent
Warwickshire v Lancashire
Gloucestershire v Worcestershire
Ties to be played 17 and 18 July