We pick a place to meet. (Say - Macca's Clifton Hill)
We set a duration for the cruise (Say - 3 hours)
We COUNT the number of starting cars and divide that into the duration.
Each car takes turns in being the cruise leader and so gets to go wherever they like for their session, continuing on from wherever we are.
We could end up anywhere!

So for example, if we have 6 cars turn up, we all take turns to drive for 30 minutes, everyone else plays "follow the leader". Could be interesting...

We may well end up a fair way away from home tho'...

Obviously if we have more cars, we take shorter turns each, or adjust the duration. - All this would be agreed to before we head off, so that everyone knows the arrangements.
Being winter, I think we should agree to stop for lunch at an indoor establishment though, so that we can get out of possibly miserable weather... (Another Maccas, a Pub, a Shopping Mall Food Court...)
Any comments? - Melbourne Guys ?