Being a Jack of all Trades is actually a poor choice when joining an already established or well-rounded group. I'm not trying to say it is a wrong choice, but read below to see my explanation.
I'm assuming that your group consist of four players as a Tank/Combat Specialist, Decker/Tech Guy, Mage/Shaman and a Face. Some of them may cross into other categories. For example, if the Tank/Combat Specialist is an adept, he may also be good at infiltration and picking locks. Your Decker deals with Matrix stuff, but also knows first aid to support post combat. Your Tech Guy/Rigger works well with machinery and computers but is also the driver and has his drones for combat, but he can also do some skills in medicine, first aid. Your Mage/Shaman can go into two secondary paths depending if they took higher skills. A Shaman can double as a face depending on the build. A hermetic can double as doctor and surgeon, and possibly as a Tech Guy should they wish to adventure into strange builds. The Face is usually in a tough spot since most of their skills will focus on Etiquette, Con and possibly the Stealth groups. But a good face will always have something to provide for the team besides good looks and a silver tongue. Most faces will have decent agility for B&E or may have magic to bring to the table, which just opens the door for them.
Here are a couple examples of a Group of 5, with 5 being the wild card player:
1) Street Sam / Tank
2) Decker / Tech Guy
3) Combat Hermetic Mage (Medic skills)
4) Face / Mystic Adept (Support Magic)
5) Infiltration / B&E - There is a lot of overlap in the magic and technical skill department. While they have someone to tank and two people capable of healing, they need someone with B&E skills such as stealth, gymnastics and so forth. This person can also double as a ranged shooter since they would have a high agility. Even with spells like improved invisibility, there is still a limitation where the mundane needs to infiltrate to get in. So someone with shooting skills and B&E would be ideal
Example 2:
1) Adept Sniper / B&E
2) Technomancer (Decknomancer)
3) Rigger (Drone and Driver)
4) Shaman / Face (Spirit focused)
5) Street Sam / Bounty Hunter - This group mainly uses spirits to "tank" for them, so showing up with Street Sam that can take punishment and dish it out would make them more well rounded. The Sniper will hardly be in direct combat and the Rigger's drones should be more for suppression and watching the Street Sam and Shaman's back. The group could also use a survivalist and someone focused on the navigation group and perception would be vital when situations arise.