To hide customs groups from search in IPS :
In Theme personnalisation (customization->theme->default and button "edit html and css") open core->front->search nodes.
Open "memberFilters" and "Filters" files.
Now search for that line (For "memberFilters" : ± line 61, at the middle For "Filters" : ± line 273, at the end)
And add just after, that piece of code :
Do the same for both files. You can adjust the "6" number to change witch groups will be hidden.
Save the both files. Enjoy !
Question to IPS expert : the first part of the code should make any group name ended with a space invisible in that list, but that doesn't work, why ? (substr function doesn't receive the right value of $group ????)