If each transaction could be "attached" to another in this way it could become very hard to censor a transaction that "the people" do not want censored. This could stop miners from censoring specific wallets or specific transactions unless they are willing to let that censorship balloon into more lost mining fees. Currently, we don't have any kind of censorship like this, but we do have lazy miners that produce small blocks about 6 times a day (I wrote a small tool here: https://fullblocks.github.io )

Please let me know if there is any way to do this currently or any BIPs that would allow for this.