I think that I am stuck on a problem that should be very easy to solve...

I have made a pivot table to extract certain parts/part numbers from a lot of assemblies.

After that I extracted the seperate parts that I needed from the pivot table in new columns seperated per type of part.
Then I added them together in the column next to it and filtered that column for unique combinaties of those parts.

The problem that I am now stuck with though is that I now have a string of numbers that consists of 2 different part numbers. So I want to untangle them.

But how do I do that when the part numbers aren't a constant length? (They can be 8/9 or 11 numbers long, and there might even be more variations that I'm not yet aware of).
All I know is that the second part numbers starts with 250, so it should be able to write a formula to seperate it based on that information I guess...

So can anyone help me with this?

For example:
number string original --> should become these separate numbers (preferably in seperate columns, but if that is done with 2 seperate formula's, that is perfectly fine).
2101305005125017770050 --> 21013050051 & 25017770050
21010850025015940050 --> 210108500 & 25015940050
21000830025015100 --> 210008300 & 25015100