There are two ways you can listen to them;
It sounds as if your scanner is not in Search mode. By default the scanner has the Search mode turned off. You can turn it on by going into the Manage Favorites list, select System, Edit Sys Option, Select ID Search, Select On. By doing this you will probably hear more than you want too. You can push Avoid when the talk groups come up and it will skip them next time.
Or you can manually add those two talk groups if that is all you want to listen too. There are several more Fire/EMS channels not yet identified.
To do that: Manage Favorites list, select system, Review/Edit system, Edit Department, Ad new Department, Ad new Channel.
It might be easier to do this through Sentinel, since you can get a better overview of what your scanner is scanning. For example if you have MARRS programmed with all the sites and talk groups you will be hearing stuff from KCMO, JOCO, East JACO, ect. If you did that and just want to listen to LS Fire then you will have to Avoid those sites and only have Less Summit on.