Combining Objects into a new model with Linq/Lambda expressions

Question

I am working on a Blazor Project and using Dapper to Pull Data from a SQL Db. I am pulling 3 tables at the moment. An entity table, a specialty table and a bridge table that is there to maintain the many to many relationship between entity and specialties.

I am able to pull from SQL fine and I want to combine the data in my data service and inject it as a new object model to the Blazor component.

Here are the models:

Entity

public class EntityModel : IEntityModel
    {
        public int Id { get; set; }
        public int PhysicianId { get; set; }
        public int PartnerId { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }

Specialty

 public class SpecialtyModel : ISpecialtyModel
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }

BridgeModel

public class BridgeModel : IBridgeModel
    {
        public int Id1 { get; set; }
        public int Id2 { get; set; }
    }

I made the properties in the bridge model generic so I could use it with another bridge table I have for a many to many relationship. The bridge tables are just two columns of IDs that link their respective tables. In this case Entity.Id and Specialty.Id

Here is the model I am combining all the information into:

 public class CombinedModel : ICombinedModel
    {
        public int Id { get; set; }
        public int PhysicianId { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public List<ISpecialtyModel> Specialties { get; set; }
    }

Here is the inside of my data service where I am stuck trying to combine the data with Linq and Lambda expressions.

 public async Task<List<IEntityModel>> ReadEntities()
        {
            var entities = await _dataAccess.LoadData<EntityModel, dynamic>("dbo.spEntity_Read", new { }, "SqlDb");
            return entities.ToList<IEntityModel>();
        }

        public async Task<List<ISpecialtyModel>> ReadSpecialties()
        {
            var specialties = await _dataAccess.LoadData<SpecialtyModel, dynamic>("dbo.spSpecialty_Read", new { }, "SqlDb");
            return specialties.ToList<ISpecialtyModel>();
        }

        public async Task<List<IBridgeModel>> ReadEntitySpecialtyBridge()
        {
            var bridge = await _dataAccess.LoadData<BridgeModel, dynamic>("dbo.spEntitySpecialty_Read", new { }, "SqlDb");
            return bridge.ToList<IBridgeModel>();
        }

        public async Task<List<ICombinedModel>> CombineData()
        {
            var entities = await ReadEntities();
            var specialties = await ReadSpecialties();
            var bridge = await ReadEntitySpecialtyBridge();

            //var combined = (from e in entities
            //                join b in bridge on e.Id equals b.Id1
            //                join s in specialties on b.Id2 equals s.Id
            //                select new CombinedModel()
            //                {
            //                    Id = e.Id,
            //                    PhysicianId = e.PhysicianId,
            //                    FirstName = e.FirstName,
            //                    LastName = e.LastName,
            //                    Specialties = new List<ISpecialtyModel>()
            //                });

            var combined = (from e in entities
                            select new CombinedModel
                            {
                                Id = e.Id,
                                PhysicianId = e.PhysicianId,
                                FirstName = e.FirstName,
                                LastName = e.LastName,
                                Specialties = specialties.Where(s =>  )
                            }
                            );

            return combined.ToList<ICombinedModel>();

This is where I am stuck. How can I write this Linq query to combine this data into the new model?

I am able to get data passed into the razor component but I am not combining it correctly and this is where I am stuck.

I hope someone can shed some light on the matter. Thank you for taking the time to look over this, I appreciate it.

With Thanks, Cesar