It is always advisable to pack an individual kit: Even if your group leader has a big kit for your group, you still need to be able to treat personal nicks and scratches. The kit your leader will be carrying will have a limited supply and the person carrying the group kit might not always be close at hand.
A good first aid kit can help you self-manage basic health problems.
Minimize bulk and weight by carrying appropriately sized quantities of your chosen items. Below is a check list of what you should carry in your first-aid kit on a backpacking trip.