One throat to hold, not three to referee
No more vendor-versus-vendor blame. One team owns the outcome, so integration is internal — not a fight you mediate.
The answer
Good instinct. Here is what that looks like.
You collapse a patchwork of vendors into one accountable team that owns the work from plan to production.
It keeps running what it builds
Delivery is not the finish line. The same team that ships the system operates it — no handoff, no knowledge walking out with the contract.
Same Slack. One team instead of many.
GIIP FDE Ops takes requests exactly the way you brief a vendor today — plain language, in a channel, no ticket ceremony. The difference is that one governed team plans, builds, deploys and operates it, so you stop being the integration layer.
Keep briefing in Slack — the difference is there is one team on the other side, and it never hands the system back.