```javascript
function parseInputSections(inputString, existingParsedData = {}) {
    // Define a regular expression pattern to match each section with headings and key/value pairs
    const sectionPattern = /##\s+(.*?)\s+([\s\S]+?)(?=\n##|\n\n##|$)/g;
    // Define a regular expression pattern to match key/value pairs
    const keyValuePattern = /^(.+?):\s*(.+)$/gm;

    // Object to store the parsed information, initialized to existingParsedData
    const parsedSections = existingParsedData;

    // Object to store the inboxes for roles and team
    const roleInboxes = existingParsedData.roleInboxes || {};
    const teamInbox = existingParsedData.teamInbox || [];

    // Match sections and iterate through them
    let sectionMatch;
    while ((sectionMatch = sectionPattern.exec(inputString)) !== null) {
        // Retrieve the section name and content
        const sectionName = sectionMatch[1].trim();
        const sectionContent = sectionMatch[2].trim();

        // Match key/value pairs within the section's content
        let keyValueMatch;
        // Create an object to store the key/value pairs
        const sectionData = {};
        while ((keyValueMatch = keyValuePattern.exec(sectionContent)) !== null) {
            // Store the key/value pairs in the object using the first captured group as key and second as value
            const key = keyValueMatch[1].trim();
            const value = keyValueMatch[2].trim();

            sectionData[key] = value;
        }

        // Special handling for 'Metadata' section
        if (sectionName === 'Metadata') {
            // ... (previous code for handling Metadata remains unchanged)
        } else if (sectionName === 'message') {
            if (sectionData.to) {
                const recipients = sectionData.to.split(',').map(role => role.trim());
                // Check if the message is addressed to the 'team'
                if (recipients.includes('team')) {
                    // Initialize 'viewedBy' array to keep track of who has viewed the message
                    sectionData.viewedBy = sectionData.viewedBy || [];
                    teamInbox.push(sectionData);
                } else {
                    // Sort the message into inboxes based on 'to' property
                    recipients.forEach(role => {
                        if (!roleInboxes[role]) {
                            roleInboxes[role] = [];
                        }
                        roleInboxes[role].push(sectionData);
                    });
                }
            }
        } else {
            // ... (existing code for handling other sections remains unchanged)
        }
    }

    // Add the role inboxes and team inbox to the parsedSections object
    parsedSections.roleInboxes = roleInboxes;
    parsedSections.teamInbox = teamInbox;

    return parsedSections;
}

// Function to view messages by a role and update the view log
function viewMessagesByRole(parsedData, roleName) {
    // Filter out messages that have already been viewed by the role
    const unseenMessages = parsedData.teamInbox.filter(message => !message.viewedBy.includes(roleName));

    // Update the view log for the messages that are being returned
    unseenMessages.forEach(message => {
        if (!message.viewedBy.includes(roleName)) {
            message.viewedBy.push(roleName);
        }
    });

    // Return the unseen messages
    return unseenMessages;
}

// Example usage:
const inputString = `
## Metadata
project: Tesla Market Research Report
role: Project Manager
task: Begin Project
details: You have received the project details. Begin by taking the first step in this project.

## message
to: team
from: Project Manager
message: This is a general announcement to the entire team.

## message
to: Research Analyst
from: Project Manager
message: Please ensure all research is aligned with our objectives and report any significant findings to the team immediately.
`;

// Parse the input string without any existing parsed data
const parsedData = parseInputSections(inputString);

// Role viewing the messages
const role = 'Project Manager';

// View unseen team messages for the 'Project Manager' role and update the view log
const unseenTeamMessages = viewMessagesByRole(parsedData, role);
console.log(unseenTeamMessages); // This will log the unseen team messages for 'Project Manager' and update the view log
```