sending postcards to someone you live with?

this may be a bit of a strange/dumb question. a friend and i love sending regular postcards to each other, even though we live in the same city. recently, due to events that are not relevant, we decided to move in together. both of us have expressed that we're a bit sad because we don't know what will happen to our postcard-sending streak, since it brings such a regular bit of joy to both of us. plus its just fun writing postcards. i don't want it to end but idk how it would work now, logistically. has anyone ever been in this situation before? i feel like it would work by dropping them off in a deposit box instead? im just not sure if im missing something