At a small business with under 10 PCs they have 3 general purpose wifi routers with internet from different ISPs.
They want to have a single network so that if they have to switch the gateway the shared folders and printers would be accessible the same way.
As they use the wifi they have enabled the DHCP for all three routers but one of them gets to be the primary so those who do not set their addresses statically will get to be on that network.
They want to switch between networks manually and not to have alternative gateways to be set automatically if one ISP is failing or similar router or client side solutions. Sometimes they are having conferences on the best ISP's line and for that time everybody who is not in the conference has to use another IP's line. Any good idea how to get rid of this networking mess and still meet the requirements?