In many cases, vassals did have their own vassals, in a process called subinfeudation. There is a link below, but it does not give as much information as I would have liked to find.
Anything the king wanted.
The vassals were in a relationship of mutual obligation with their superior lords or kings. They provided an oath of allegiance and support in exchange for land,...
A vassal was a person who swore allegiance and homage to a lord. In exchange for this, he got property consisting of an estate or estates from which he could get income as the serfs who lived there...
A vassal was a person who had gone into a mutual obligation with a monarch or feudal lord. The monarch or lord got the vassal's allegiance and homage. In exchange the vassal got land and protection....
The relationship between a vassal and the church was the same as the relationship between any other secular person and the church. The vassal was part of the feudal hierarchy, and the church had a...