It's possible to add WIFI interfaces to RUTX11. Please take a look to this link, click on add and you can set up the new interface according with your needings.
You can also call both frequencies 2.4 and 5Ghz with the same name, but would be better if you can identify which SSID are you using.
SSID1: RUT_2.4Ghz (802.11 b/g/n/)
SSID2: RUT_5Ghz (802.11 n/a/c)
SSID1: RUT_IOT_2.Ghz (802.11 b/g/n/)
According with this link, it can set up up to 100 connections by interface. but if you'll use LTE connections, would be great to perform tests because the connection speed can be compromised when using LTE data, (It'll depends of your operator (ISP).
Any further doubt please let me know.