If you mean Steam Family then no. You can only be a member of a single Steam Family at any given time.
Also if you leave a Steam Family you need to wait 1 year from the moment you joined till you can join/create another family.

Originally posted by (DJ) SUPER OMA👍👍👍👍:

i was playing tf2 when suddently i thought about getting the items from poker night at the inventory 1 and 2,but i dont have one.I heard that i can get to family with PNATI for 2-3 keys,but I am already in family with my friends.Is this possible?

And don't buy your way into a Steam Family.

Steam family share has restrictions.
1. You can only be in one family group at a time.
2. There 12 MONTHS / 1 YEAR restriction before can join another family group.

Originally posted by (DJ) SUPER OMA👍👍👍👍:

i was playing tf2 when suddently i thought about getting the items from poker night at the inventory 1 and 2,but i dont have one.I heard that i can get to family with PNATI for 2-3 keys,but I am already in family with my friends.Is this possible?

They can kick you whenever they want from the family group, on top of that if they invite your account as child account they can do recovery on your account, as well you can't choose to leave the group without their permission, or support help.