Display setting to hide unit type when there is only one unit per type

Our problem requires 1 calendar for all unit types together.
But we only have one unit per unit type.

This gives for a messy ui with after every other line a blank line

Our stupid fast fix, hide the type lines with css.
#calendar div.fc-rows tr:nth-child(odd){
display: none;
}

This only works if there is always only one unit per unit-type

Solution would be to add a nice class in the type rows

2 images before and after,
in before image the orange is used to highlight the rows that need to be hidden in our case