We are a project that for external reasons has to run in a Scrumish fashion. We consist of two subprojects : A backend data and services provider that I am a part of, and a UI+BPM layer that interacts with it.
The backend also serves a few other consumers and both parts are implemented in two completely separate stacks (by different vendors). The developers of either side are experts on the tool set of their vendor and have no knowlege about the respective other technology or functional design. It's to the point where we don't have the slightest idea what the others are talking about at the daily standup meetings and we are completely incapable of estimating stories from the other side of the aisle.
On the other we still have to release together, have a lot of points where we interact and sit in the same room. We have the same PM, PO and SM and some of the testers work both sides. In total we are 7-9 developers and 3-4 testers and a few other roles at the meeting each morning. We cannot easily be trained on the respective other stack or functional design, for budget, licensing and time reasons. So from a budget and project sponsorship point of view this is one big project whereas from the inside it is more likely two.
In the beginning we had our standups, review, retro and planning as one team but with separate refinements. After a while the discontent with the boredom at sprint changes led to the review, retro and planning being split into two different appointments and the sprints are now ending one week apart.
How would you implement something like scrum better in this setting? Is there a value in continuing to run an inclusive daily or should it also be split? If we keep it together how do we improve it? If we split it, how do we make sure the important interteam questions get addressed?