How many SSH keys for each user?

I need to load more than one SSH key for a single user.
Is this possible just like plain OpenSSH? How to?

where is the problem adding another key in the way you added the first one?

/user ssh-keys print 
Flags: R - RSA, D - DSA 
 #   USER                       BITS KEY-OWNER
 0 D admin                      1024
 1 D admin                      2048
 2 R admin                      2048

No problem at all. Simply it seems to me it’s not stated that I can set up more ssh keys. So I was scared to “overwrite” the first key with the second one. Thanks.

while you stay logged in and do not close the session you can do whatever you want with the user or keys.