I've enjoyed a few minutes of multi-girl action at the old LMP...a bargain considering I only paid the party fee.
If you want a longer session with 6 hotties, you're looking at big money...and it would be a pig to arrange!
You might be able to do 4 or 5 girls at a parlour type venue if you were sufficiently known to them to be reliable for around £500-600 per hour.
6 girls overnight to a hotel suite would likely be £4-5,000...one for the Arabs, Russians, lottery winners...and dreamers!!