240v #12/2 help and timer

Hi I have a 240v double pole breaker that is connected with a #12 /2 line was used for a baseboard in my garage but now I put a fireplace so no need for the baseboards. Can I connect them to a 240 v pool/light timer split the 240 into 120s and share the neutral from a nearby circuit? To light my yard? With the 2 outputs. It’s a regular intermatic timer ..... Been curious? Don’t really want to run another line it’s about 30ft from the house