I am not sure I understand the ask...
I don't understand the logic behind the claims you have so I'll use the generic claims. Let's say you have the following claims:
- Claim1
- Claim2
- Claim3
You would like to set Claim3 as a multi value claim with the values of Claim1 and Claim2. You would do the following:
c:[Type == "Claim1"] => issue(Type = "Claim3", Value = c.Value);
and
c:[Type == "Claim2"] => issue(Type = "Claim3", Value = c.Value);
You issue the claim Claim3 twice so it is now "multi value". Does this help?