Eidim Zommemin are conspiring witnesses, which have a whole Perek of Gemara that talk about them: the first perek in Makkot.
My question is: the first set says edut. The second one claims they are conspiring witnesses and with them on that date in a certain location. What happens if the first set then says that the second was with them at the incident?
i.e. the second set claims they were in Chevron, and the first one claims they were in Los Angeles, and that the second set was with them in Los Angeles.
If this were possible, it would create a huge problem for the halacha of eidim zommemin - the first set could just say that the second was with them in a different place.
So, is this possible?