Matching values in different rows and columns

[lolwat00000]

Hello, I have a dataset that looks like this, there is a matching key that goes in zig-zag pattern, there could be more than 3 changes

Input:

Source	Target
aaa	bbb
111	222
bbb	ccc
ccc	ddd
+++	---

Output needed:

Source	Target
aaa	ddd
111	222
bbb	ddd
ccc	ddd
+++	---

I have done it using Join tool, but would like to see if there's a better way to solve it

I have tried Make Group tool but it seems it will fail if the combination is like below, where it outputs 777 - 999 instead of 999 - 777:

Source	Target
999	777

Thanks!