Can I do it?

[computerdude2018]

connect 2 routers to 1 modem! I am looking to have different SSID's, and I want to connect 2 routers (Generic router from ISP and Linksys WRT 1200ac v.1 Smart WiFi router). Please provide expert opinions.

 

[jsmithepa]

U can connect 3, 4, 5.... configure them as Access Point and there won't be any routing issues.

 

[Alabalcho]

You cannot connect directly two (or more) routers to single cable/ADSL modem. You can cascade them (and in that case devices connected to second router will "see" devices connected to first one), or use just APs (Access Points) to create different SSIDs.

However, for "expert opinion" a well defined problem is important. Apart from "different SSIDs" (and why), what else is needed?