>Is it possible to have a one-to-many-to-many grid?
>Are there third-party softwares that have developed such
>a grid?
It's possible to have a one-to-many-to-many-to-many... grid or browse. You could do it with relations, SQL cursor or view. The most practical of them seem to be a view.

* Like FP 2.x style browse
use tableA in 0 alias Parent
use tableB in 0 alias Child1 order tag Child1order
use tableC in 0 alias Child2 order tag Child2order
select Child1
set relation to RelKey into Child2
select Parent
set relation to RelKey into Child1
set skip to Child1,Child2
with thisform.myGrid
 .recordsource = "Parent"
 .columncount = 5
 .columns(1).controlsource = "parent.field1"
 .columns(2).controlsource = "parent.field2"
 .columns(3).controlsource = "child1.field1"
 .columns(4).controlsource = "child2.field1"
 .columns(5).controlsource = "child2.field2"
endwith

*Using a view
with thisform.myGrid
 .recordsource = "MyView"
 .columncount = 5
 .columns(1).controlsource = "myView.field1"
 .columns(2).controlsource = "myView.field2"
 .columns(3).controlsource = "myView.field3"
 .columns(4).controlsource = "myView.field4"
 .columns(5).controlsource = "myView.field5"
endwith

Setting via a view is easier using view designer and grid builder.
Cetin