How can I add to values together and divide by 2

Hi All,

Don’t know if this is the correct place to ask this question? I have the below data being gather by an inputs.snmp, if represents my 2 different voice gateways. My question is I am trying to add these 2 values together and then divide by 2 to get the actual ITSP sip calls. My question is how would I do this on a annunciator graph?

Below is the output from telegraf:
agent_host=,host=sip-monitor.,hostname=C4331-VGW1 CvCallVolConnActiveConnection=18i 1532094025000000000
agent_host=,host=sip-monitor,hostname=C4331-VGW1 CvCallVolConnActiveConnection=37i 1532094025000000000

This is what I have in the panel:

Thanks for you guidance.

I figured it out, did a regex for the 2 host and sampled the mean value for both metrics.

can you share your solution? i am trying to add 2 metrics together and couldnt figure it out for many days now.