2 PLAYER BRACKET. Setup by choosing 2 offensive players the will be shared between 2 defenders. In this case, U and D are bracketing blue 4 and 7. U is stopping their under cuts, D is stopping deep cuts. All the other players are playing normal match D. This is also how a male/fem zone would work when there's only 3 of that gender on the field for that point.
This work easily when the bracketed players go in different directions
But if they both go under, the deep bracket will need to follow the deeper of the cutters under.
The two defenders should be communicating and ready to switch.
If one of the attackers being bracketed gets the disc, the under defender should take the mark and the deep defender plays 1v1 defence until the disc is thrown again.
3 PLAYER FEM/MALE ZONE. Works the same as a bracket, but with an extra player (B) protecting the break side if there's 4 of that gender on the field. The 4th defender will match a handler, or the most dangerous opponent of that gender.
If one of the poached players gets the disc, the break side defender should take the mark until the next throw, even if it takes some time to get there. This effectively turns the zone into a 2 person bracket defence for that one throw.
Any male/fem zone or bracketing should transition back to a normal match defence once the disc advances to our defensive brick mark.
Against a side stack, a bracket still works well - it's clear who the offensive targets are, so the 2 defenders (U and D) can surround the primary cutters.
Both players should continue to communicate and be aware of the poached player (likely in the side stack) becoming active.