How to pass attribute dynamically in URL from RPC function

Custom Apps
,
1

Hello,
I have module where I want to show dropdown from RPC function call.
My scenario is I have two dropdown :-
First dropdown : Fetches all the accounts by an rpc function “rpc://getAccounts”
Second dropdown : Fetches all the custom feed list for above account selected by an rpc function “rpc://getCustomFeedList”

First rpc is working fine, I get all the accounts in the dropdown and I have set key as accounts and value as accountId

Problem is in the second rpc function :
When I try to select from drop down its returning 404 error.
So I have kept acountId static “145632”, but I want this dynamic.
How to do?
Second RPC function ::
{
“url”: “/accounts/{{parameters.accountId}}/custom-feeds”,
//“url”: “/accounts/145632/custom-feeds”,
“method”: “GET”,
“qs”: {},
“body”: {},
“headers”: {},
“response”: {
“iterate”: “{{body.data}}”,
“output”: {
“label”: “{{item.attributes.name}}”,
“value”: “{{item.id}}”
}
}
}

First RPC function : Working well.
{
“url”: “/accounts”,
“method”: “GET”,
“qs”: {},
“body”: {},
“headers”: {},
“response”: {
“iterate”: “{{body.data}}”,
“output”: {
“label”: “{{item.attributes.name [item.attributes.subscription]}}”,
“value”: “{{item.id}}”
}
}
}

Please provide some help to resolve this.