Can you put someone's car on your insurance so they don't have to pay a higher rate for their own coverage?

"Basicly... insurance ... my mommy and I were required to sustain an SR 22 for 36 months. We got our initial one. which was our existing provider then they stated they wont renew the policy with us anymore... and we had to discover another company decided allstate... Because insurance were the people willing to offer an SR-22 FOR BRAND SPANKING NEW procedures. We've had allstate for six months... Their costs are very expensive though... With SR-22... we got estimates from statefarm... They're great... But they WOn't supply SR-22s with new guidelines. However in addition they explained...additionally they refuse to offer it with Current policies too... Is that this even possible? we have 3 vehicles. We were thinking of preserving one vehicle with allstate