WLAN BRIDGE HOTSPOT

Hy =)

I have a question, i have a main router and there i have two WIFI networks. (one privat and one guest WIFI) WORKS perfektly
Next i have a hap lite from mikrotik and i like to use this as repeater.
But i like to use there the guest WIFI (HOTSPOT) client connect via web with user and password, but when i like to connect hap lite with the router i only can use the privat WIFI but not the HOTSPOT because i need a passphrase and i dont have one for guest wifi…

edit.: i cant connect the two router via cable i only can use WIFI BRIDGE

What can i do ?
Can anyone help me ?

Thx a lot…
kind regards
dave