Make a replace in panel

I’m on grafana/zabbix and i have two similar item

item stream = test1.test1.test1-test1.2018-10-02
item function = test1-test1-test1-test1-2018-10-02-s3

i will like to show the two value on different grah base on de value $stream

i mean if i select the vaiable test1.test1.test1-test1.2018-10-02 as variable
i would like to make a replace to change . by - in the second graf to show the second metric

how can i do that