Tracking Personal expenses for Nonprofit

Hi, we are a non-profit, and for various events we conduct, individual people usually buy items that may be expenses or assets, and we reimburse them when we receive funds. How do we keep track of this and account for it. We need to keep track of the balances that we owe to each of these people. For e.g. if a person buys an item from Office Depot, we still want to enter the vendor as Office Depot itself. But the payment was done using that individuals credit card and we would like to reimburse that.

In quickbooks I used to maintain separate GL account for each of these people. There should be a better way.