When logged in to the device, click advanced, then in the left menu under QoS choose User Groups. Create the two groups here, with the Ip ranges each vlan uses. Save.
Then choose bandwidth control, Group Bandwidth Reservation and choose those groups and specify the limits you want. save & apply.
what software are you on? you can add up to 10 groups (or is it 10+ the original three? dont remember) on firmware i think 8.4.1 and above.
EDIT: sorry, I may have misunderstood. are you meaning that the sliders won’t show more than three groups? if so, i don’t think you can add more there.
They increase it to 10 in user groups at 8.4.0.
" Increased QoS User Groups to 10 and updated the Content Blocking page to support 10 User Groups for the Exempted User Group Table "