I suspect that this will not sufficiently answer your question (or at the very least show my naïveté, but I'll give it a go.
I'm a newish computer science student. I have the most familiarity with Ethereum Virtual Machine based architectures. They are becoming more abundant in the space. I also want to preface this by saying that I know the implementation here is non-trivial.
Essentially in any case there would need to be read/write functionality with custom-metadata on Hive, an efficient way to keep track of the sequencing of the data, and a way to pass messages as a verifier to/from another blockchain.
I know that this sounds a whole lot like a bridge (because it is really), but it'd be nice if this could be integrated into Hive nodes through plugins because it might encourage the expansion of the number of nodes within the ecosystem. Some of the bridges being built for Hive are nice but they tend to want to be their own thing, or aren't permissionless. This detracts from the value that could be added to Hive if it did this out of the box. I get that there are many moving parts, and that it would have to be substantially tested, but I think it would be worth it.
All of that said, if this is even remotely possible, I'd be willing to give it a go.