How to add flags or marks to tcp net.connect() for later ip rule based routing

Question

In my network I have multiple endpoints (devices) behind multiple vpn edge routers.

The edge routers have all different ip addresses.

The endpoints (devices) behind the egde routers have all the same ip addresses.

For example, the monitor endpoints (devices) have always the ip address 192.168.155.5

To access the enpoints (devices) there are rule based routings active on the vpn server (host)

So different clients from lan can use rule based routing by there internal lan (src) ip addresses. That works perfect.

Now we want to have an external access by a web proxy.

extern/target1
extern/target2

For that the packets came all from the same internal lan ip (src) address (proxy).

And therefore the ip (src) rule based routing does not work here.

How to set a MARK to tcp packets when using node.js net.connect().

For example I want to set MARK 1 for connections by extern/target1 and MARK 2 for extern/target2.

If possible, it will be possible to use rule based routing by marks.

Thanks for help in advance