How do you manage picking up objects in multiplayer?

I have the following problem. I want to pick up an object, something like "grab the flag", or "pick the car" or whatever you want to.

The issue is that in multiplayer, you may have 10 people running towards that car and I have to decide which of them gets them first. There is only one car available.

Right now, if i do an RPC call to "pickcar", then on the RPC check if someone has it and if not, set it... then I have that problem that the first call several players because of lag get that nobody has the car and they all pick it up at the same time.

Any ideas how to go about this so that only one player ends up picking up the car?