KiCost alternative part

In KiCost how to add two part numbers to the same component as alternative part? Because sometime you are producing two version of the same board.

And other question, sometimes you have to assembly a connect that use two “part components” (e.g., plastic + metal contact) ordered as separated components. How to add this two numbers to the same symbol?

Is it possible to add in manf#
“part1 OR part2”
“part1 AND part2”

Is it possible to merge 2 .xml BoM files to create just one spreadsheet?

Not possible within KiCAD - 1 part per symbol only.
If you create a script that parses the BOM and converts a special multi-part-number symbol entry (from your personal library) into several part number lines in an extended BOM, you should be on the same track as some other users…
See @Andy_P 's method of doing things with a post-processing script…

There is a issue opened in GitHub to this implementation, that will work fine for me.