This type of merge (shown as the second dialog screen capture above) relies on a set of coded target points, either individual coded target points or Letter Sheets (see Letter Sheet Automated Target Projects) that are static and common between the merge projects. The static/common points must not have moved between the projects. You must have at least 3 non-linear common merge target points, but ideally more with good spread to ensure a good merge/fit. All other targets in the project can be moved and reused in the other merge projects.
Projects to be merged are added to the list at top left using the Add Project… button. Click Remove Project to remove one from the list.
When a project is selected in the Projects list up top, the grid below populates with the other merge projects. Enter a list of target IDs that are common to the selected project above with the selected project in the grid. The IDs can be listed in a comma or space separated list (e.g. 51,52,53,54,55 or 51 52 53 54 55), or with dashes and commas (e.g. 51-55,57,112-115). You can also enter a Letter Sheet letter (e.g. 51, 52, 53, 54, 55, A, B) which will get automatically translated into a list of the associated 6 target IDs on that Letter Sheet. Repeat for the other projects listing the common target point IDs between them.
Once the shared points are established, click the Execute Merge button. Warnings will appear if there are problems with the setup, but if all goes well, the coded targets will be re-coded and renamed for reference, while the merge target points will tie the two projects together.
Note that if there are more than two projects merged, not all projects need to share the same static points. The merge is done on a pairwise basis, so, for example, Project 1 and Project 2 can share points 51,52,53,54,55 while Project 2 and Project 3 can share static points 56,57,58,59,60.