You would have to have each peer send a message with the relevant information to the host, and the host relay that message to peers. Use tags to facilitate logic to decide what gets sent to who.
Generally speaking, such an approach will not solve your lag problem. On the other hand, if your project is for school only, your host and your peers should all be local, in which case the internet quality doesn't matter at all.
If you don't have a good understanding of the difference between host, server, and signalling server, recommend going through the multiplayer tutorials again carefully, or you'll have bigger issues than just lag down the line.