Can I use a router with a connection that requires a login from web?

I have a internet connection from PMPL. Unlike, BSNL, in which I was given a phone line and hence needed a modem, they have given me a direct LAN connection. What I have to do to get connected is, I have to plug that cable in and open a site, and log in with my ID password that they have provided. The thing is, with this process I can use the internet on only one machine at one time. Can I use a Wifi router, say Netgear, and thus make the connection accessible to all the devices [mobile, tablets, etc] in my home?

How will I login if I use a router? Can I switch to always connected mode, like in BSNL, with this connection as well? Or will I have to use it only on one machine at a time?

Any help will be appreciated,
Thanks.

You wont be able to run this on always on. You would need to login using the browser or client if they have supplied one and then you should be able to connect on other devices as well provided you are logged in to the ISP from one of them. It is similar to using Tata wimax or sify because it will be exactly the same setup for you. I am sure I wrote about this a few years ago. Please use the search function.