Merge Dynamic AutoCAD Blocks

I have two existing dynamic blocks in AutoCAD—a crane chassis plan and a separate upper cab plan—that need to sit perfectly together. The task is to position the cab so its reference point is coincident (concentric where applicable) with the matching point on the chassis while leaving each block completely independent; every original stretch, flip, rotate, and visibility parameter already embedded in the individual blocks must remain untouched.

Here is what I expect once the file comes back to me:
• The two blocks are precisely aligned at the specified snap points I will mark in the DWG you receive.
• Neither block is converted into a single composite dynamic block; their internal parameters still behave exactly as they do now.
• No unintended scaling, rotation, or parameter loss occurs during the merge.

Return the updated DWG and a brief note describing what reference points you used so I can repeat the approach on future models. If this first merge goes smoothly, I have several more crane assemblies waiting for the same treatment, so a clear, repeatable workflow is important. AutoCAD 2021 is my primary environment, so please work natively or ensure full compatibility.