### FEATURE REQUEST

Currently, when a bitcoin node is set up with a connection to both TOR and normal IPv4/6 internet, the 8 outbound-only connection slots, almost always get filled with nodes connecting over IP.
Adding a config option, which would try to ballance these connections based on what kind of network they go through, would be benefficial in many ways:

1. It would add edges between bitcoin network on TOR and normal internet, reducing delays, and the risks associated with an attacker isolating a part of TOR-bitcoin-network from the rest of the world
(Or an ISP/government man-in-the-middling all the normal IP connections)

2. It would help hide/annonymise normal user's transactions from his/her ISP, by mixing them with TOR-outbound ones

3. It would reduce the stress on normal general purpose TOR exit nodes, as users would more likely/reliably connect to TOR-IPv4/6 bitcoin nodes instead of exiting into normal internet first, and then connecting to default IPv4/6-only bitcoin nodes

I understand it is possible to create such bridges already, by forcing connections to TOR-only nodes, or by just running a node with lots of inbound slots, but I think the proposed option, would greatly increase the number of such relays, and remove the need for user to maintain a TOR-node whitelist, by handing this work off to normal bitcoind connection finding algorithm.

This could be implemented as a minimum number of connections for each network, or just a simple evening boolean switch. (Which could be enabled by default for bitcoind installs with TOR connectivity)

In the future, if bitcoin was to support a new network type (for example cjdns/I2P/GNUnet), this option would help establish a presence on the new network faster

bitcoind: 0.15
_("Failed to listen on any port. Use -listen=0 if you want this."),
                "", CClientUIInterface::MSG_ERROR);
        }
        return false;
    }
    proxyType i2p_sam;
    if (GetProxy(NET_I2P, i2p_sam)) {
        m_i2p_sam_session = std::make_unique<i2p::sam::Session>(GetDataDir() / "i2p_private_key",
                                                                i2p_sam.proxy, &interruptNet);
    }
    for (const auto& strDest : connOptions.vSeedNodes) {
        AddAddrFetch(strDest);
    }
    if (clientInterface) {
        clientInterface->InitMessage(_("Loading P2P addresses...").translated);
    }
    
    int64_t nStart = GetTimeMillis();
    {
        CAddrDB adb;
        if (adb.Read(addrman))
            LogPrintf("Loaded %i addresses from peers.dat  %dms\n", addrman.size(), GetTimeMillis() - nStart);
        else {
            addrman.Clear(); 
            LogPrintf("Recreating peers.dat\n");
            DumpAddresses();
        }
    }
    if (m_use_addrman_outgoing) {