Let's say we are 4 people and we want to purchase something that is currently worth 10 coins. When we click the purchase button, we are presented with an address to transfer the coins within 15 minutes.
The question: Should we send the necessary coins in a single transaction? Or is it possible to make (for example) 4 different transactions of (for example) 2.5 btc each, summing in 10 btc? If so, what if one of us cannot make the transfer on time?
Any information/experience is appreciated.