No gaps before certain activities?

[pnlshd]

Hello,

I want a certain set of activities (one or more) to not have a gap before them. The students set has a max of 1 gap per week and when I make it zero the timetable doesn't generate or takes a long time.

I don't mind if they get that gap before another activity in any other day or even in the same day but not before the certain activity or set of activities that I have.

Is there is a workaround to do this or to make max gaps per certain day for this students set =0?
(Because I know the day that this activity will be in)

Thanks in advance!