Proximity Spawning is a setting per default disabled Gameplay setting which can has two options:
Enabled/Disabled Tickbox
1m-100m Slider
When enabled, whenever you would want to spawn on a squad member that is in combat, it instead spawns you on the nearest squad member that is not in Combat up to a maximum distance in meter set at the Slider.
This would prevent situations in which you can't spawn on a bunch of team members because you keep clicking the 2 out of, let's say 5 people that are in combat.
Alternatively (and in hindsight the easier option) just add an option to not make In-Combat Teammates clickable/selectable as spawn option, so it naturally chooses spawnable teammates over in-combat ones when clicking on a pile of squadmates.